pro·le·gom·e·non (prō'lĭ-gŏm'ə-nŏn', -nən) n.
pl.pro·le·gom·e·na (-nə)
A preliminary discussion, especially a formal essay introducing a work of considerable length or complexity.
prolegomena(used with a sing. or pl. verb) Prefatory remarks or observations.
[Greek, from neuter present passive participle of prolegein, to say beforehand : pro-, before; see pro-2 + legein, to speak; see leg- in Indo-European roots.] pro'le·gom'e·nous adj.
1652, "learned preamble to a book," from Gk. prolegomenon, neuter passive prp. of prolegein "to say beforehand," from pro- "before" + legein "to speak" (see lecture) + suffix -menos (as in alumnus). The same sense is in preface.