a. and sb. Zool. [f. mod.L. Union- UNIO.] a. adj. Of or belonging to the Unionidæ; unioniform. b. sb. A unionid (Cent. Dict., 1891).
1879. H. A. Nicholson, Palæont. (ed. 2), I. 492. Unionoid Bivalves, with thick shells.
a. and sb. Zool. [f. mod.L. Union- UNIO.] a. adj. Of or belonging to the Unionidæ; unioniform. b. sb. A unionid (Cent. Dict., 1891).
1879. H. A. Nicholson, Palæont. (ed. 2), I. 492. Unionoid Bivalves, with thick shells.
