To make some change in; make different in some particular; cause to vary in some degree, without an entire change.To change entirely or materially; convert into another form or state: as, to alter a cloak into a coat; to alter an opinion.To castrate, emasculate, or spay, as an animal.To exchange.To agitate: as, ”altered and moved inwardly,” Milton, Areopagitica, p. 1.To become different in some respect; vary; change.