melanism
noun
mel·a·nism
ˈme-lə-ˌni-zəm 
1
: an increased amount of black or nearly black pigmentation (as of skin, feathers, or hair) of an individual or kind of organism compare industrial melanism
2
: intense human pigmentation of the skin, eyes, and hair
Examples of melanism in a Sentence
Recent Examples on the Web
This discrepancy surprised us because the genetic mutation that causes melanism occurs less frequently than the one that causes albinism/leucism.
—
Elizabeth Carlen, Discover Magazine, 31 Oct. 2024
As pollution levels declined due to regulation, the melanism in these creatures reversed.
—Smithsonian Magazine, Smithsonian Magazine, 29 Mar. 2023
To determine the origins of squirrel melanism, or dark coloration, McRobie and colleagues from Cambridge University and the Virginia Museum of Natural History extracted DNA from gray and fox squirrel specimens found in North America.
—Meilan Solly, Smithsonian, 16 Aug. 2019
The animal is melanistic—its genes carry a mutation that creates more dark pigment than light pigment, according to Eduardo Eizirik, a biologist and cat-melanism expert at Pontifical Catholic University of Rio Grande do Sul in Brazil.
—Sergio Pitamitz, National Geographic, 22 Mar. 2017
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Elizabeth Carlen, Discover Magazine, 31 Oct. 2024
As pollution levels declined due to regulation, the melanism in these creatures reversed.
—Smithsonian Magazine, Smithsonian Magazine, 29 Mar. 2023
To determine the origins of squirrel melanism, or dark coloration, McRobie and colleagues from Cambridge University and the Virginia Museum of Natural History extracted DNA from gray and fox squirrel specimens found in North America.
—Meilan Solly, Smithsonian, 16 Aug. 2019
The animal is melanistic—its genes carry a mutation that creates more dark pigment than light pigment, according to Eduardo Eizirik, a biologist and cat-melanism expert at Pontifical Catholic University of Rio Grande do Sul in Brazil.
—Sergio Pitamitz, National Geographic, 22 Mar. 2017
Cite this Entry
“Melanism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/melanism. Accessed 3 Nov. 2025.
Copy CitationKids Definition
melanism
noun
mel·a·nism
ˈmel-ə-ˌniz-əm
: an exceptionally dark coloring (as of skin, feathers, or hair) of an individual or kind of living thing
Medical Definition
melanism
noun
mel·a·nism
ˈmel-ə-ˌniz-əm
1
: an increased amount of black or nearly black pigmentation (as of skin, feathers, or hair) of an individual or kind of organism
2
: intense human pigmentation in skin, eyes, and hair
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