Why is the ninth month called September?
also moult, mid-14c., mouten, of feathers, "to be shed," from Old English *mutian "to change" (cf. bemutian "to exchange"), from Latin mutare "to change" (see mutable). Transitive sense, of birds, "to shed feathers" is first attested 1520s. With parasitic -l-, late 16c., on model of fault, etc. Related: Molted, moulted; molting, moulting. As a noun from 1815.
v. molt·ed, molt·ing, molts
To shed periodically part or all of a coat or an outer covering, such as feathers, cuticle, or skin, which is then replaced by a new growth. n.
The act or process of molting.
The material cast off during molting.