Definition from Wiktionary, the free dictionary
- A French surname.
- Charles Messier (1730-1817); a French astronomer who in 1774 published Nebulae and Star Clusters, a catalogue of 45 deep sky objects such as nebulae and star clusters. The purpose of the catalogue was to help comet hunters (like himself) and other astronomical observers to distinguish between permanent and transient objects in the sky. Objects in Messier's catalog are numbered, and the letter M (for Messier) is prepended to these numbers, as in M31 (the Andromeda Galaxy) or M13 (the globular cluster in Hercules).