noun, plural abacuses, abaci. [ab-uh-sahy, -kahy, uh-bak-ahy] /ËÃ¦b ÉËsaÉª, -ËkaÉª, ÉËbÃ¦k aÉª/ (Show IPA) 1. a device for making arithmetic calculations, consisting of a frame set with rods on which balls or beads are moved. 2. Architecture. a slab forming the top of the capital of a column. Origin of abacus.
Sulfate is any salt or ester made up of sulphuric acid. Sulfide is used to describe any of three types of chemical compounds that contain sulfur. Sulfite is sulfur dioxide, or SO2.
sulfa drug. sulfa drug, any of a class of synthetic chemical substances derived from sulfanilamide, or para-aminobenzenesulfonamide. Sulfa drugs are used to treat bacterial infections, although they have largely been replaced for this purpose by antibiotics; some are also used in the treatment of diabetes.