CRASIS

in classical Greek, the contraction of two vowels or diphthongs at the end of one word and the beginning of an immediately following word, as kn for ka n or houms for ho ems. Crasis is especially common in some lyric poetry and in Old Comedy. The term sometimes refers to word-internal contraction in Latin, as nil from nihil. The word is from the Greek krsis, literally, mixing or blending.