The reversal of an electric current.
The change to a lesser penalty or punishment by the State
Substitution, as a means of discriminating between phonemes.
The process or habit of journeying to and from work on a regular basis; commuting.
Substitution of one thing for another; interchange.
Specifically, the substitution of one kind of payment for another, especially a switch to monetary payment from obligations of labour.
An electrical switch, in a generator or motor, that periodically reverses the direction of an electric current.
A binary map in a given group G, given by [g, h] = ghg⁻¹h⁻¹, where g and h are elements of G, which yields the group's identity if and only if the group operation commutes for g and h.
A binary map in a given ring R, given by [a, b] = ab − ba, where a and b are elements of R, which yields the ring's zero element if and only if the multiplication operation commutes for a and b.