Ptolemy, Latin in full Claudius Ptolemaeus, (born c. 100 ce—died c. 170 ce), an Egyptian astronomer, mathematician, and geographer of Greek descent who flourished in Alexandria during the 2nd century ce.

What did Ptolemy invent?

Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics. He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.

What does Ptolemy mean?

1 : of or relating to the second century geographer and astronomer Ptolemy of Alexandria and especially to his belief that the earth is at the center of the universe with the sun, moon, and planets revolving around it the Ptolemaic system.