HETEROCLITE, in Grammar, an irregular or anomalous word, which, either in declension, conjugation, or regimen, deviates from the ordinary rules of grammar. The word is Greek, ἱτεροκλίτης, formed from ἱτερος, alter, another, different, and κλίμα, I decline. Heteroclitic is more peculiarly applied to nouns which vary or are irregular in point of declension.