In grammar, the changing of things mutually depending on each other; reciprocal conversion; as, the master of the servant, the servant of the master.

Among the ancients, that part of a song or dance, before the altar, which was performed by turning from west to east, in opposition to the strophy. The ancient odes consisted of stanzas called strophies and antistrophies, to which was often added the epode. These were sung by a choir, which turned or changed places when they repeated the different parts of the ode. The epode was sung, as the chorus stood still.