Elision, << ih LIHZH uhn, >> in poetry, means dropping or slurring a syllable to keep close to the meter of the poem. An example occurs in the line “Or trade the memory of this night for food” from Edna St. Vincent Millay’s “Love is not all: it is not meat nor drink.” The word memory, ordinarily pronounced as three syllables (mem-uh-ree), can be read as two syllables (mem-ree) by dropping its second syllable. This elision gives the line 10 syllables, the usual number for the poem’s iambic pentameter lines.
Before the 1900’s, poets often marked an elision for the reader by using an apostrophe. For example, the word never would be written ne’er.