# Euclid[**yoo**klid], Gr **Eucleides**(4th--3rd-cBC) Greek mathematician who taught in Alexandria c.300BC, and who was probably the founder of its mathematical school. His chief extant work is the 13-volume *Elements*, which became the most widely known mathematical book of Classical antiquity, and is still much used in geometry. The approach which obeys his axioms became known as *Euclidean geometry*. |