Scrabble?! CANCELLABLE

Definitions of CANCELLABLE in various dictionaries:

In mathematics, the notion of cancellative is a generalization of the notion of invertible. An element a in a magma (M, ) has the left cancellation property (or is left-cancellative) if for all b and c in M, a b = a c always implies that b = c. An element a in a magma (M, ) has the right cancellation property (or is right-cancellative) if for all b and c in M, b a = c a always implies that b = c. An element a in a magma (M, ) has the two-sided cancellation property (or is cancellative) if it is both left- and right-cancellative. A magma (M, ) has the left cancellation property (or is left-cancellative) if all a in the magma are left cancellative, and similar definitions apply for the right cancellative or two-sided cancellative properties. A left-invertible element is left-cancellative, and analogously for right and two-sided. For example, every quasigroup, and thus every group, is cancellative.