abecedarius, a type of acrostic in which the first letter of each line of a poem or the first letter of the first word of each stanza taken in order forms the alphabet. Examples of these are some of the Psalms (in Hebrew), such as Psalms 25 and 34, where successive verses begin with the letters of the Hebrew alphabet in order. The word is from the late Latin for “alphabetical” and is derived from the names of the letters a, b, c, and d.