| Word | Definitions | Synonyms |
|---|---|---|
| nyctalopia | (noun) inability to see clearly in dim light; due to a deficiency of vitamin A or to a retinal disorder | Synonyms: moon blindness, night blindness |
| nyctophobia | (noun) a morbid fear of night or darkness | - |
| nycturia | (noun) excessive urination at night; especially common in older men | Synonyms: nocturia |