propaedeutic n.

word-forming element meaning "forward, forth, toward the front" (as in proclaim, proceed); "beforehand, in advance" (prohibit, provide); "taking care of" (procure); "in place of, on behalf of" (proconsul, pronoun); from Latin pro (adv., prep.) "on behalf of, in place of, before, for, in exchange for, just as," which also was used as a first element in compounds and had a collateral form por-.

Also in some cases from cognate Greek pro "before, in front of, sooner," which also was used in Greek as a prefix (as in problem). Both the Latin and Greek words are from PIE *pro- (source also of Sanskrit pra- "before, forward, forth;" Gothic faura "before," Old English fore "before, for, on account of," fram "forward, from;" Old Irish roar "enough"), extended form of root *per- (1) "forward," hence "in front of, before, toward, near," etc.

The common modern sense of "in favor of, favoring" (pro-independence, pro-fluoridation, pro-Soviet, etc.) was not in classical Latin and is attested in English from early 19c.

before vowels ped-, word-forming element meaning "boy, child," from Greek pedo-, combining form of pais "boy, child," especially a son, from PIE root *pau- (1) "few, little." The British form paed- is better because it avoids confusion with the ped- that means "foot" (from PIE root *ped-) and the ped-that means "soil, ground, earth." Compare, from the same root, Sanskrit putrah "son;" Avestan puthra- "son, child;" Latin puer "child, boy," Oscan puklu "child."