a a number of lines of writing, such as a poem, certain letters of which form a word, proverb, etc. A single acrostic is formed by the initial letters of the lines, a double acrostic by the initial and final letters, and a triple acrostic by the initial, middle, and final letters
b the word, proverb, etc, so formed
c (as modifier) ■ an acrostic sonnet
[C16: via French from Greek akrostikhis, from acro- + stikhos line of verse, stich]