Wallace, known as a stickler for correct usage, at IJ pp. 386, uses enjambment to mean simply ‘jammed in’:
This segues into an entr’acte, with continent squeezed in for world in ‘It’s a Small World After All,’ which enjambment doesn’t do the rhythm section of doo-wopping girls a bit of good, but does usher in the start of a whole new era.
That’s a good, but I don’t think technically correct, use of the word. Enjambment means the content of one line of poetry spilling into the next line of poetry. What Wallace is describing is a word with three syllables being said in the space of a word with one syllable, — which is actually kind of the opposite.
.i`` * ^ / . . . . . ` `~ 