| polymyxin | (noun) any of several toxic antibiotics obtained from a particular soil bacterium | - |
|---|
| poplin | (noun) a ribbed fabric used in clothing and upholstery | - |
|---|
| poppin | (adjective) Of an event that is taking place and is lively | - |
|---|
| porcelain | (noun) ceramic ware made of a more or less translucent ceramic | - |
|---|
| porphyrin | (noun) any of various pigments distributed widely in living tissues | - |
|---|
| poudrin | (noun) small crystals of ice | Synonyms: diamond dust, frost mist, frost snow, ice crystal, ice needle, snow mist |
|---|
| pravastatin | (noun) an oral drug (trade name Pravachol) administered to reduce blood cholesterol levels; recommended after nonfatal heart attacks | Synonyms: Pravachol |
|---|
| prazosin | (noun) antihypertensive drug (trade name Minipress) | Synonyms: Minipress |
|---|
| precipitin | (noun) an antibody that causes precipitation when it unites with its antigen | - |
|---|
| preordain | (verb) foreordain or determine beforehand | Synonyms: foreordain, predestine |
|---|
| proaccelerin | (noun) a coagulation factor | Synonyms: accelerator factor, factor V, prothrombin accelerator |
|---|
| proconvertin | (noun) a coagulation factor formed in the kidney under the influence of vitamin K | Synonyms: cothromboplastin, factor VII, stable factor |
|---|
| progestin | (noun) any of a group of steroid hormones that have the effect of progesterone | Synonyms: progestogen |
|---|
| prolactin | (noun) gonadotropic hormone secreted by the anterior pituitary; in females it stimulates growth of the mammary glands and lactation after parturition | Synonyms: lactogenic hormone, luteotropin |
|---|
| prostaglandin | (noun) a potent substance that acts like a hormone and is found in many bodily tissues (and especially in semen); produced in response to trauma and may affect blood pressure and metabolism and smooth muscle activity | - |
|---|
| protein | (noun) any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk and legumes | - |
|---|
| prothrombin | (noun) a protein in blood plasma that is the inactive precursor of thrombin | Synonyms: factor II |
|---|
| protirelin | (noun) hormone released by the hypothalamus that controls the release of thyroid-stimulating hormone from the anterior pituitary | Synonyms: thyrotropin-releasing factor, thyrotropin-releasing hormone, TRF, TRH |
|---|
| protohemin | (noun) a reddish-brown chloride of heme; produced from hemoglobin in laboratory tests for the presence of blood | Synonyms: hemin |
|---|
| provitamin | (noun) vitamin precursor; a substance that is converted into a vitamin in animal tissues | - |
|---|
| psilocin | (noun) a hallucinogenic compound obtained from a mushroom | Synonyms: psilocybin |
|---|
| (noun) a substituted tryptamine alkaloid and a serotonergic psychedelic substance, present in most psychedelic mushrooms together with its phosphorylated counterpart psilocybin. | Synonyms: psilocine, psilocyn, psilotsin |
| psilocybin | (noun) a hallucinogenic compound obtained from a mushroom | Synonyms: psilocin |
|---|
| psilotsin | (noun) a substituted tryptamine alkaloid and a serotonergic psychedelic substance, present in most psychedelic mushrooms together with its phosphorylated counterpart psilocybin. | Synonyms: psilocin, psilocine, psilocyn |
|---|
| ptomain | (noun) any of various amines (such as putrescine or cadaverine) formed by the action of putrefactive bacteria | Synonyms: ptomaine |
|---|
| ptyalin | (noun) an amylase secreted in saliva | - |
|---|
| puffin | (noun) any of two genera of northern seabirds having short necks and brightly colored compressed bills | - |
|---|
| pumpkin | (noun) usually large pulpy deep-yellow round fruit of the squash family maturing in late summer or early autumn | - |
|---|
| (noun) a coarse vine widely cultivated for its large pulpy round orange fruit with firm orange skin and numerous seeds; subspecies of Cucurbita pepo include the summer squashes and a few autumn squashes | Synonyms: autumn pumpkin, Cucurbita pepo, pumpkin vine |
| purloin | (verb) make off with belongings of others | Synonyms: abstract, cabbage, filch, hook, lift, nobble, pilfer, pinch, snarf, sneak, swipe |
|---|
| pushpin | (noun) a tack for attaching papers to a bulletin board or drawing board | Synonyms: drawing pin, thumbtack |
|---|
| pyocyanin | (noun) a toxic blue crystalline antibiotic found in green pus | - |
|---|
| pyroxylin | (noun) highly flammable nitrocellulose used in making collodion and plastics and lacquers | Synonyms: pyroxyline |
|---|
| quatrain | (noun) a stanza of four lines | - |
|---|
| quin | (noun) one of five children born at the same time from the same pregnancy | Synonyms: quint, quintuplet |
|---|
| quoin | (noun) (architecture) solid exterior angle of a building; especially one formed by a cornerstone | Synonyms: corner |
|---|
| (noun) the keystone of an arch | Synonyms: coign, coigne |
| (noun) expandable metal or wooden wedge used by printers to lock up a form within a chase | Synonyms: coign, coigne |
| ragamuffin | (noun) a dirty shabbily clothed urchin | Synonyms: tatterdemalion |
|---|
| rain | (noun) anything happening rapidly or in quick successive | Synonyms: pelting |
|---|
| (noun) water falling in drops from vapor condensed in the atmosphere | Synonyms: rainfall |
| (noun) drops of fresh water that fall as precipitation from clouds | Synonyms: rainwater |
| (verb) precipitate as rain | Synonyms: rain down |
| raisin | (noun) dried grape | - |
|---|
| ramekin | (noun) a small fireproof dish used for baking and serving individual portions | Synonyms: ramequin |
|---|
| (noun) a cheese dish made with egg and bread crumbs that is baked and served in individual fireproof dishes | Synonyms: ramequin |
| ramequin | (noun) a small fireproof dish used for baking and serving individual portions | Synonyms: ramekin |
|---|
| (noun) a cheese dish made with egg and bread crumbs that is baked and served in individual fireproof dishes | Synonyms: ramekin |
| ratlin | (noun) (nautical) a small horizontal rope between the shrouds of a sailing ship; they form a ladder for climbing aloft | Synonyms: ratline |
|---|
| reagin | (noun) an immunoglobulin E that is formed as an antibody against allergens (such as pollen); attaches to cell membranes causing the release of histamine and other substances responsible for the local inflammation characteristic of an allergy | - |
|---|
| refrain | (noun) the part of a song where a soloist is joined by a group of singers | Synonyms: chorus |
|---|
| (verb) choose not to consume | Synonyms: abstain, desist |
| (verb) resist doing something | Synonyms: forbear |
| regain | (verb) get or find back; recover the use of | Synonyms: find, recover, retrieve |
|---|
| (verb) come upon after searching; find the location of something that was missed or lost | Synonyms: find |
| rein | (noun) one of a pair of long straps (usually connected to the bit or the headpiece) used to control a horse | - |
|---|
| (noun) any means of control | - |
| (verb) keep in check | Synonyms: harness, rule |
| (verb) stop or slow up one's horse or oneself by or as if by pulling the reins | Synonyms: rein in |
| (verb) stop or check by or as if by a pull at the reins | Synonyms: rein in |
| (verb) control and direct with or as if by reins | Synonyms: draw rein, harness, rein in |
| rejoin | (verb) answer back | Synonyms: come back, repay, retort, return, riposte |
|---|
| (verb) join again | - |
| relaxin | (noun) hormone secreted by the corpus luteum during the last days of pregnancy; relaxes the pelvic ligaments and prepares the uterus for labor | - |
|---|
| remain | (verb) stay the same; remain in a certain state | Synonyms: rest, stay |
|---|
| (verb) be in a certain place and not leave | Synonyms: persist, stay, stay put, stick, stick around |
| (verb) continue in a place, position, or situation | Synonyms: continue, stay, stay on |
| (verb) be left; of persons, questions, problems, results, evidence, etc. | - |
| renin | (noun) a proteolytic enzyme secreted by the kidneys; catalyzes the formation of angiotensin and thus affects blood pressure | - |
|---|
| rennin | (noun) an enzyme that occurs in gastric juice; causes milk to coagulate | Synonyms: chymosin |
|---|
| resin | (noun) any of a class of solid or semisolid viscous substances obtained either as exudations from certain plants or prepared by polymerization of simple molecules | Synonyms: rosin |
|---|
| resorcinolphthalein | (noun) a yellow dye that is visible even when highly diluted; used as an absorption indicator when silver nitrate solution is added to sodium chloride in order to precipitate silver chloride (turns pink when no chloride ions are left in solution and negative fluorescein ions are then absorbed) | Synonyms: fluorescein, fluoresceine, fluorescent dye |
|---|
| restrain | (verb) prevent the action or expression of | Synonyms: hold back, keep, keep back |
|---|
| (verb) to close within bounds, or otherwise limit or deprive of free movement | Synonyms: confine, constrain, hold |
| (verb) restrict (someone or something) so as to make free movement difficult | Synonyms: cumber, encumber |
| (verb) prevent (someone or something) from doing something | - |
| retain | (verb) keep in one's mind | - |
|---|
| (verb) secure and keep for possible future use or application | Synonyms: hold, hold back, keep back |
| (verb) allow to remain in a place or position or maintain a property or feature | Synonyms: continue, keep, keep on |
| (verb) hold back within | - |
| retrain | (verb) train again | - |
|---|
| (verb) teach new skills | - |
| rhodopsin | (noun) a red photopigment in the retinal rods of vertebrates; dissociates into retinene by light | Synonyms: retinal purple, visual purple |
|---|
| ribavirin | (noun) an inhaled antiviral agent (trade name Virazole) that may be used to treat serious virus infections | Synonyms: Virazole |
|---|
| riboflavin | (noun) a B vitamin that prevents skin lesions and weight loss | Synonyms: hepatoflavin, lactoflavin, ovoflavin, vitamin B2, vitamin G |
|---|
| ricin | (noun) a toxic protein extracted from castor beans; used as a chemical reagent; can be used as a bioweapon | Synonyms: ricin toxin |
|---|
| rifampin | (noun) an antibacterial drug (trade names Rifadin and Rimactane) used to treat tuberculosis | Synonyms: Rifadin, Rimactane |
|---|
| robin | (noun) large American thrush having a rust-red breast and abdomen | Synonyms: American robin, Turdus migratorius |
|---|
| (noun) small Old World songbird with a reddish breast | Synonyms: Erithacus rubecola, Old World robin, redbreast, robin redbreast |
| rosin | (noun) any of a class of solid or semisolid viscous substances obtained either as exudations from certain plants or prepared by polymerization of simple molecules | Synonyms: resin |
|---|
| (verb) rub rosin onto | - |
| ruin | (noun) destruction achieved by causing something to be wrecked or ruined | Synonyms: laying waste, ruination, ruining, wrecking |
|---|
| (noun) a ruined building | - |
| (noun) an event that results in destruction | Synonyms: ruination |
| (noun) failure that results in a loss of position or reputation | Synonyms: downfall, ruination |
| (noun) the process of becoming dilapidated | Synonyms: dilapidation |
| (noun) an irrecoverable state of devastation and destruction | Synonyms: ruination |
| (verb) fall into ruin | - |
| (verb) destroy completely; damage irreparably | Synonyms: destroy |
| (verb) reduce to ruins | - |
| (verb) deprive of virginity | Synonyms: deflower |
| (verb) reduce to bankruptcy | Synonyms: bankrupt, break, smash |
| (verb) destroy or cause to fail | - |
| sabin | (noun) a unit of acoustic absorption equivalent to the absorption by a square foot of a surface that absorbs all incident sound | - |
|---|
| saccharin | (noun) a crystalline substance 500 times sweeter than sugar; used as a calorie-free sweetener | - |
|---|
| safranin | (noun) any of a class of chiefly red organic dyes | Synonyms: saffranine, safranine |
|---|
| sainfoin | (noun) Eurasian perennial herb having pale pink flowers and curved pods; naturalized in Britain and North America grasslands on calcareous soils; important forage crop and source of honey in Britain | Synonyms: esparcet, holy clover, Onobrychis viciaefolia, Onobrychis viciifolia, sanfoin |
|---|
| salicin | (noun) an anti-inflammatory agent that is produced from willow bark. | - |
|---|
| saligenin | (noun) Salicylic alcohol, also called saligenin, is a crystalline phenolic alcohol with the chemical formula C7H8O2, that is obtained usually by hydrolysis of salicin. | Synonyms: salicylic alcohol |
|---|
| salvinorin | (noun) a hallucinogen obtained from Salvia divinorum | - |
|---|
| sanfoin | (noun) Eurasian perennial herb having pale pink flowers and curved pods; naturalized in Britain and North America grasslands on calcareous soils; important forage crop and source of honey in Britain | Synonyms: esparcet, holy clover, Onobrychis viciaefolia, Onobrychis viciifolia, sainfoin |
|---|
| sannyasin | (noun) a Hindu religious mendicant | Synonyms: sannyasi, sanyasi |
|---|
| saponin | (noun) any of various plant glucosides that form soapy lathers when mixed and agitated with water; used in detergents and foaming agents and emulsifiers | - |
|---|
| sarin | (noun) a highly toxic chemical nerve agent that inhibits the activity of cholinesterase | Synonyms: GB |
|---|
| satin | (noun) a smooth fabric of silk or rayon; has a glossy face and a dull back | - |
|---|
| savarin | (noun) a sponge cake baked in a ring mold | - |
|---|
| savin | (noun) procumbent or spreading juniper | Synonyms: dwarf juniper, Juniperus sabina |
|---|
| saxitoxin | (noun) a powerful neurotoxin produced by certain dinoflagellates found in red tides; it can accumulate in mollusks that feed on the dinoflagellates and cause food poisoning to humans | - |
|---|
| scarfpin | (noun) a pin used to hold the tie in place | Synonyms: tie tack, tiepin |
|---|
| scatterbrain | (noun) a flighty and disorganized person | Synonyms: forgetful person |
|---|
| scleroprotein | (noun) a simple protein found in horny and cartilaginous tissues and in the lens of the eye | Synonyms: albuminoid |
|---|
| sculpin | (noun) any of numerous spiny large-headed usually scaleless scorpaenoid fishes with broad mouths | - |
|---|
| sealskin | (noun) a garment (as a jacket or coat or robe) made of sealskin | - |
|---|
| (noun) the pelt or fur (especially the underfur) of a seal | Synonyms: seal |
| searobin | (noun) American gurnard; mostly found in bays and estuaries | Synonyms: sea robin |
|---|
| secretin | (noun) a gastrointestinal hormone that stimulates the secretion of water and bicarbonate from the pancreas and bile ducts whenever the stomach empties too much acid into the small intestine | - |
|---|
| sequin | (noun) adornment consisting of a small piece of shiny material used to decorate clothing | Synonyms: diamante, spangle |
|---|
| serin | (noun) any of various brown and yellow finches of parts of Europe | - |
|---|
| serotonin | (noun) a neurotransmitter involved in e.g. sleep and depression and memory | Synonyms: 5-hydroxytryptamine |
|---|
| sharkskin | (noun) a smooth crisp fabric | - |
|---|
| sheepskin | (noun) a document certifying the successful completion of a course of study | Synonyms: diploma |
|---|
| (noun) tanned skin of a sheep with the fleece left on; used for clothing | Synonyms: fleece |
| (noun) skin of a sheep or goat prepared for writing on | Synonyms: lambskin, parchment |
| shin | (noun) the inner and thicker of the two bones of the human leg between the knee and ankle | Synonyms: shin bone, shinbone, tibia |
|---|
| (noun) the front part of the human leg between the knee and the ankle | - |
| (noun) the 22nd letter of the Hebrew alphabet | - |
| (noun) a cut of meat from the lower part of the leg | Synonyms: shin bone |
| (verb) climb awkwardly, as if by scrambling | Synonyms: clamber, scramble, shinny, skin, sputter, struggle |
| siderophilin | (noun) a globulin in blood plasma that carries iron | Synonyms: beta globulin, transferrin |
|---|
| simvastatin | (noun) an oral lipid-lowering medicine (trade name Zocor) administered to reduce blood cholesterol levels; recommended after heart attacks | Synonyms: Zocor |
|---|
| sin | (noun) an act that is regarded by theologians as a transgression of God's will | Synonyms: sinning |
|---|
| (noun) estrangement from god | Synonyms: sinfulness, wickedness |
| (noun) the 21st letter of the Hebrew alphabet | - |
| (noun) ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle | Synonyms: sine |
| (verb) commit a sin; violate a law of God or a moral law | Synonyms: transgress, trespass |
| (verb) commit a faux pas or a fault or make a serious mistake | Synonyms: blunder, boob, drop the ball, goof |
| sirloin | (noun) the portion of the loin (especially of beef) just in front of the rump | - |
|---|
| siskin | (noun) small yellow-and-black Eurasian finch with a sharp beak | Synonyms: Carduelis spinus |
|---|
| skein | (noun) coils of worsted yarn | - |
|---|
| skin | (noun) body covering of a living animal | Synonyms: hide, pelt |
|---|
| (noun) an outer surface (usually thin) | - |
| (noun) a bag serving as a container for liquids; it is made from the hide of an animal | - |
| (noun) a natural protective body covering and site of the sense of touch | Synonyms: cutis, tegument |
| (noun) the rind of a fruit or vegetable | Synonyms: peel |
| (noun) a member of any of several British or American groups consisting predominantly of young people who shave their heads; some engage in white supremacist and anti-immigrant activities and this leads to the perception that all skinheads are racist and violent | Synonyms: skinhead |
| (noun) a person whose head is bald or shaved | Synonyms: baldhead, baldpate, baldy, skinhead |
| (noun) a person's skin regarded as their life | - |
| (verb) remove the skin from | Synonyms: pare, peel |
| (verb) remove the bark of a tree | Synonyms: bark |
| (verb) bruise, cut, or injure the skin or the surface of | Synonyms: scrape |
| (verb) climb awkwardly, as if by scrambling | Synonyms: clamber, scramble, shin, shinny, sputter, struggle |
| slain | (adjective) killed; `slain' is formal or literary as in "slain warriors" | - |
|---|
| (noun) people who have been slain (as in battle) | - |
| smidgin | (noun) a tiny or scarcely detectable amount | Synonyms: iota, scintilla, shred, smidge, smidgen, smidgeon, tittle, whit |
|---|
| somatotrophin | (noun) a hormone produced by the anterior pituitary gland; promotes growth in humans | Synonyms: growth hormone, human growth hormone, somatotrophic hormone, somatotropic hormone, somatotropin, STH |
|---|