noun
1. : a sign - used in mathematics to require subtraction (as in 8-6.2) or designate a negative quantity (as in -10°) — compare plus sign
2. : a sign - used in logic to indicate exception or exclusion (as in a-b to indicate the class of A's excepting the B's) or abstraction among concepts (as in “human-rational” to indicate those attributes that man has in common with other animals)