/proh'li gom"euh non', -neuhn/ , n. , pl. prolegomena /-neuh/ .
1. a preliminary discussion; introductory essay, as prefatory matter in a book; a prologue.
2. Usually, prolegomena . ( sometimes used with a sing. v. ) a treatise serving as a preface or introduction to a book.
[ 1645-55; prolegómenon, neut. of pass. prp. of prolégein to say beforehand, equiv. to pro- PRO- 2 + légein to say (akin to lógos LOGOS) ]