Definition - The omission of vowels, consonants, or syllables from a word or phrase so that it is easier to pronounce.
Note: This is in contrast to ellipsis, which is the omission of words from a sentence.

Example -
la - 'bor - a - tor - y becomes 'la - bra - tor - y

Etymology -
The word derives from the Latin elidere, crush out (from ex, out + laedere, to strike).

Oxford English Dictionary -
Its first citation is from 1581:
"The Italian is so full of Vowels, that it must ever be cumbred with Elisions."
(Sidney Apol. Poetrie (Arb.) 70)

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