| Word | Definitions | Synonyms |
|---|---|---|
| quincentenary | (adjective) of or relating to a 500th anniversary | Synonyms: quincentennial |
| quincentennial | (adjective) of or relating to a 500th anniversary | Synonyms: quincentenary |
| quinquefoliate | (adjective) (of a leaf shape) having five leaflets | - |
| quintessential | (adjective) representing the perfect example of a class or quality | - |
| quintillionth | (adjective) the ordinal number of one quintillion in counting order | - |
| quintuple | (adjective) having five units or components | Synonyms: five-fold, fivefold |