Source : WordNet®

proton
     n : a stable particle with positive charge equal to the negative
         charge of an electron

Source : Free On-Line Dictionary of Computing

PROTON
     
        1. A home computer made by {Acorn Computers} under a contract
        won from the {BBC} in April 1981.
     
        [Details?]
     
        2. Something to do with {Microsoft} {SoftLib}?
     
        (1994-11-28)