abacusyoudaoicibaDictYouDict[abacus 词源字典]
abacus: [17] Abacus comes originally from a Hebrew word for ‘dust’, ’ābāq. This was borrowed into Greek with the sense of ‘drawing board covered with dust or sand’, on which one could draw for, among other purposes, making mathematical calculations. The Greek word, ábax, subsequently developed various other meanings, including ‘table’, both in the literal sense and as a mathematical table.

But it was as a ‘dust-covered board’ that its Latin descendant, abacus, was first used in English, in the 14th century. It was not until the 17th century that the more general sense of a counting board or frame came into use, and the more specific ‘counting frame with movable balls’ is later still.
[abacus etymology, abacus origin, 英语词源]
abacus (n.)youdaoicibaDictYouDict
late 14c., "sand table for drawing, calculating, etc.," from Latin abacus, from Greek abax (genitive abakos) "counting table," from Hebrew abaq "dust," from root a-b-q "to fly off." Originally a drawing board covered with dust or sand that could be written on to do mathematical equations. Specific reference to a counting frame is 17c. or later.