elision

noun

1. the omission, assimilation, or slurring over of a vowel, syllable, etc. in pronunciation: often used in poetry to preserve meter, as when a word ends with a vowel before another word beginning with a vowel (Ex.: “th' inevitable hour”)
2. any act or instance of leaving out or omitting a part or parts

Origin: L elisio, a striking out (in LL, elision) < pp. of elidere: see elide