From Old English ræfter, of Germanic origin, related to the origin of raft.
释义（英文）
名词Noun
(architecture) One of a series of slopedbeams that extend from the ridge or hip to the downslope perimeter or eave, designed to support the roof deck and its associated loads.
(added to verbs) A person or thing that does an action indicated by the root verb; used to form an agent noun. · (added to verbs, informal) A person or thing to which the root verb is done or can be done satisfactorily.