algorithm al·go·rithm /ˈalɡəˌriT͟Həm/ Learn to pronounce noun noun: algorithm ; plural noun: algorithms a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer. "a basic algorithm for division" Origin late 17th century (denoting the Arabic or decimal notation of numbers): variant (influenced by Greek arithmos ‘number’) of Middle English algorism , via Old French from medieval Latin algorismus . The Arabic source, al-Ḵwārizmī ‘the man of Ḵwārizm’ (now Khiva), was a name given to the 9th-century mathematician Abū Ja‘far Muhammad ibn Mūsa, author of widely translated works on algebra and arithmetic. Photograph By Michael Dziedzic