Messier number

Meaning

Noun

• A catalogue number used to identify any one of more than one hundred galaxy, nebula, and other deep-sky objects visible in the night sky; the designation formed by the surname Messier or letter M being prepended to the number, as in Messier 31 or M31 (the Andromeda Galaxy).

Origin

• From Charles Messier (1730-1817), the French astronomer who first published his Catalogue of Nebulae and Star Clusters in 1774.