1. pro- a prefix, having anti- as its opposite, used to form adjectives that have the general sense “favoring” the group, interests, course of action, etc., denoted by the headword: pro-choice; pro-American; prowar.
2. pro- a prefix occurring in loanwords from Latin, with the meanings “forward,” forming esp. verbs denoting forward movement or location (proceed; progress), advancement (promote; propose), or bringing into existence (procreate; produce); “before, outside of” (profane); “in place of” (pronoun).
3. pro- a prefix, occurring orig. in loanwords from Greek, with the meanings “before, beforehand, in front of” (prognosis; prophylactic; prothesis), “front part, extremity” (proboscis), “primitive or embryonic form,”“precursor” (prodrug; pronephros; prosimian).
Etymology: (< Gk, comb. form of pró for, before; see pro1)
Definition of 'pro-'
Webster Dictionary
1. pro- a prefix signifying before, in front, forth, for, in behalf of, in place of, according to; as, propose, to place before; proceed, to go before or forward; project, to throw forward; prologue, part spoken before (the main piece); propel, prognathous; provide, to look out for; pronoun, a word instead of a noun; proconsul, a person acting in place of a consul; proportion, arrangement according to parts
Definitions of pro- 
Afrikaans: pro
Arabic: بادِئَه معناها: نَصير، مُ
Bulgarian: про-
Brazilian: pró-
Czech: pro-
German: pro-...
Danish: pro-
Greek: φιλο- (ως α΄ συνθ.)
Spanish: pro
Estonian: pooldaja
Farsi: موافق؛ هوادار
Finnish: -mielinen
French: pro-
Hebrew: בְּעָד
Hindi: पक्ष में
Hungarian: támogató, -barát
Indonesian: pro
Icelandic: fylgjandi
Italian: pro-
Japanese: －ひいきの
Korean: 친-
Lithuanian: pro-
Latvian: pro-; (kaut kā) piekritēj
Malay: pro-
Dutch: pro-
Norwegian: -vennlig
Polish: pro-
Persian: موافق؛ هوادار
Pashto: موافق،هم نظره
Portuguese: pró-
Romanian: pro-
Russian: про-
Slovak: pro-
Slovenian: pro-
Serbian: pro-
Swedish: pro-, -vänlig
Thai: สนับสนุน
Turkish: ... yanlısı, ... taraftar
Taiwanese: 表示`親
Ukrainian: про-
Urdu: کي حمايت ميں
Vietnamese: ủng hộ ai; thân
Chinese: 表示＂亲＂
