The Collaborative International Dictionary of English v.0.48:

minus \mi"nus\ (m[imac]"n[u^]s), n.; pl. minuses
   (m[imac]"n[u^]s*[-e]z).
   A factor counted as a disadvantage; a loss or potential loss
   in a situation or plan; as, he added up all the pluses and
   minuses and decided not to do it; as, the lack of money is a
   big minus in an election campaign.
   [PJC]