legal
     adj 1: established by or founded upon law or official or accepted
            rules [ant: {illegal}]
     2: of or relating to jurisprudence; "legal loophole"
     3: having legal efficacy or force; "a sound title to the
        property" [syn: {sound}]
     4: relating to or characteristic of the profession of law; "the
        legal profession"
     5: allowed by official rules; "a legal pass receiver"
Source: WordNet® 2.0

legal adj. Loosely used to mean `in accordance with all the relevant
   rules', esp. in connection with some set of constraints defined by
   software. "The older =+ alternate for += is no longer legal syntax in
   ANSI C." "This parser processes each line of legal input the moment it
   sees the trailing linefeed." Hackers often model their work as a sort of
   game played with the environment in which the objective is to maneuver
   through the thicket of `natural laws' to achieve a desired objective.
   Their use of `legal' is flavored as much by this game-playing sense as
   by the more conventional one having to do with courts and lawyers.
   Compare {language lawyer}, {legalese}.


Source: The Jargon File