Pronunciation: (ab'u-kus, u-bak'us),[key] —n., —pl.ab•a•cus•es, ab•a•ciPronunciation: (ab'u-sī", -kī", u-bak'ī).[key] 1. a device for making arithmetic calculations, consisting of a frame set with rods on which balls or beads are moved.
2. Archit. a slab forming the top of the capital of a column. See diag. under column.