Onocentaur, on-o-sen′tawr, n. a kind of centaur, half-man, half-ass.
Onoclea, on-ō-klē′a, n. a genus of aspidioid ferns, with contracted fertile fronds. [Gr. onos, a vessel, kleiein, to close.]
Onology, ō-nol′ō-ji, n. foolish talk.
Onomantic, on-ō-man′tik, adj. pertaining to On′omancy or (obs.) Onomat′omancy, divination by names. [Gr. onoma, a name, manteia, divination.]
Onomastic, on-ō-mas′tik, adj. pertaining to a name, esp. pertaining to the signature to a paper written in another hand.—n. Onomas′ticon, a list of words: a vocabulary. [Gr., from onoma, a name.]
Onomatology, on-ō-ma-tol′o-ji, n. the science of, or a treatise on, the derivation of names.—n. Onomatol′ogist, one versed in such. [Gr. onoma, onomatos, name, logia—legein, to discourse.]
Onomatopœia, on-ō-mat-o-pē′ya, n. the formation of a word so as to resemble the sound of the thing of which it is the name: such a word itself, also the use of such a word, as 'click,' 'cuckoo'—also Onomatopoē′sis, or Onomatopoiē′sis.—adjs. Onomatopœ′ic, Onomatopoet′ic. [Gr. onoma, -atos, a name, poiein, to make.]
Onset, on′set, n. violent attack: assault: storming. [On and set.]
Onshore, on′shōr, adj. toward the land.
Onslaught, on′slawt, n. an attack or onset: assault. [A.S. on, on, sleaht, a stroke.]