ecthlipsis

ecthlipsis

(ɛkˈθlɪpsɪs)
n, pl ecthlipses
the elision of a syllable beginning with a short vowel and ending with an m when that syllable occurs at the end of a word and before another word beginning with either a vowel or an h

ecthlipsis

(in Latin prosody) the elision of the last syllable of a word ending in m when the following word begins with a vowel.
See also: Verse