Real Dictionary

pro
countable noun: A pro is a professional.

PRO in American English
public relations officer (or office)
abbreviation: proline
abbreviation: public relations officer

pro in American English 1
a person who favors the affirmative side of some debatable question
favorable
favorably disposed toward; for
on the affirmative side; favorably
adverb: in favor of a proposition, opinion, etc.
noun: a proponent of an issue; a person who upholds the affirmative in a debate

pro in American English 2
professional (sense 3) professional (sense 4)
noun: professional

pro in American English 3
noun

PRO in British English
abbreviation for: Public Records Office

pro in British English 1
adverb: in favour of a motion, issue, course of action, etc

pro in British English 2
adjective
the internet domain name for: professional practitioner

pro-
prefix: You can add pro- to adjectives and nouns in order to form adjectives that describe people who support or admire a particular person, system, or idea.

pro- in American English 1
before in place or time
prefix: a prefix indicating favor for some party, system, idea, etc., without identity with the group (pro-British; pro-Communist; proslavery), having anti- as its opposite

pro- in American English 2
moving forward or ahead of
prefix: a prefix identical in meaning with pro-1, occurring in words borrowed from Greek (prodrome) or formed of Greek (and occasionally Latin) elements

pro- in British English 1
prefix: in favour of; supporting

pro- in British English 2
prefix: before in time or position; anterior; forward