melanocyte-stimulating hormone
noun
: any of several vertebrate hormones of the pituitary gland that darken the skin by stimulating melanin dispersion in pigment-containing cells
Example Sentences
Recent Examples on the Web Johnson thought the most likely mechanism would be melanocytes—skin cells that contain pigment—and another hormone known as MSH, or melanocyte-stimulating hormone. 
Jennifer Ouellette, Ars Technica, 11 July 2022 During pregnancy, there even appear to be higher levels of what’s known as melanocyte-stimulating hormone. Korin Miller, SELF, 27 Aug. 2018
Jennifer Ouellette, Ars Technica, 11 July 2022 During pregnancy, there even appear to be higher levels of what’s known as melanocyte-stimulating hormone. Korin Miller, SELF, 27 Aug. 2018 Word History
First Known Use
1953, in the meaning defined above
Medical Definition
melanocyte-stimulating hormone
noun
: either of two vertebrate hormones of the pituitary gland that darken the skin by stimulating melanin dispersion in pigment-containing cells —abbreviation MSH
called also intermedin, melanophore-stimulating hormone, melanotropin