I.a rule or level, used by carpenters, masons, etc.: amussis: tabula, quā utuntur ad saxa leviganda, Varr. ap. Non. p. 9, 17; Aus. Idyll. 16, 11; cf. Sisenn. ap. Charis. p. 178 P.; Paul. ex Fest. p. 6 Müll. —In class. Lat. in the adv. phrases,
ămussis , is, f. etym. unc.; perh. from am- and assis = axis, a plank, i. e. something flat, straight, moved about a surface in adjusting it (acc. amussim, v. Neue, Formenl. I. p. 198; abl. and plur. not used; only ante- and post-class.),