Source : Free On-Line Dictionary of Computing

trit
     
         /trit/ (By analogy with "{bit}") One base-3 digit; the
        amount of information conveyed by a selection among one of
        three equally likely outcomes.  Trits arise, for example, in
        the context of a {flag} that should actually be able to assume
        *three* values - such as yes, no, or unknown.  Trits are
        sometimes jokingly called "3-state bits".  A trit may be
        semi-seriously referred to as "a bit and a half", although it
        is linearly equivalent to 1.5849625 bits (that is, log2(3)
        bits).
     
        [{Jargon File}]
     
        (1995-05-11)