Lewis Short
(adjective) : sescuncĭa (SESCONCIA, Inscr. Orell. 4563), ae, f. sesqui-uncia
* One and a half unciae, i.e. a twelfth and a half, = one eighth of a whole, Plin. 36, 25, 62, § 187; Cels. 5, 18, 28; Col. 12, 59, 4; Scrib. Larg. 50; 60; Front. Aquaed. 26; Dig. 37, 8, 7 fin.—As : copulae sescunciae,an inch and a half thick,Plaut. Ep. 5, 1, 11; cf. the foll. art.
Charlton T. Lewis, Charles Short, A Latin Dictionary