Look up abacus in Wiktionary, the free dictionary.
An abacus is a counting frame.
Abacus may also refer to:
- Abacus (architecture), a flat slab forming the uppermost member or division of the capital of a column
- Abacus (journal), a peer-reviewed academic accounting journal
- Abacus school, a type of Renaissance-era Italian trade school
- Logical abacus, an early mechanical digital computer
- Mental abacus, a system involving visualization of an abacus to carry out arithmetical calculations
- Abacus Harmonicus, an ancient diagram showing the structure and placement of the keys of a particular musical instrument
- Operation Abacus, the Canadian military operation to restore vital services if the year 2000 caused disruption