O / ŏpĭfĭcĭum
noun

ŏpĭfĭcĭum

gen. ŏpĭfĭcii · gender neuter · decl. 2nd
a working; the doing of a work; a work
a working, the doing of a work, a work (ante- and post-class), Varr. R. R. 3, 16: in opificiis opera, App. Flor. n. 9.