Another of my experimental entries in the little Bible glossary, a definition of the acrostic form.
Acrostic — A Hebrew poetic form in which the first letters in each line are in alphabetical order. Examples are Ps 25, 34, 145 and Pr 31:10-31. Some poems repeat the letters such as Ps 37 (twice), Lam 4 (two times), Lam 1-3 (three times), Ps 119 (8 times). Somes acrostics are irregular. Its effect is “a poetic way of saying that a total coverage of the subject was being offered” (NIDB). Acrostics are not reproduced in the major English Bible versions.