Meaning

1. war (organized, large-scale, armed conflict between countries or between national, ethnic, or other sizeable groups, usually but not always involving active engagement of military force)
2. war (particular conflict of this kind)
3. war (any protracted conflict)
4. war (any of a family of card games where all cards are dealt at the beginning of play and players attempt to capture them all, typically involving no skill and only serving to kill time)
5. (obsolete) military service