leucism

noun

leu·​cism ˈlü-ˌsi-zəm How to pronounce leucism (audio)
: an abnormal condition of reduced pigmentation affecting various animals (such as birds, mammals, and reptiles) that is marked by overall pale color or patches of reduced coloring and is caused by a genetic mutation which inhibits melanin and other pigments from being deposited in feathers, hair, or skin
leucistic
lü-ˈsi-stik How to pronounce leucism (audio)
adjective

Examples of leucism in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The orca's pale complexion may be due to leucism or Chediak-Higashi Syndrome. — Fernando Cervantes Jr., USA TODAY, 5 Dec. 2024 There are a variety of causes of leucism, such as genetic, autoimmune and other disorders that result in a partial loss of melanin, Norton said. — Natalie Davies, Freep.com, 22 Oct. 2025 However, leucism — a separate condition — can also produce white coloration in whales, according to LiveScience, meaning not all whales with an ivory complexion are true albinos. — Brendan Rascius, Miami Herald, 30 June 2025 Some studies suggested potential ecological costs, but others, including our own work on deep-sea species such as the angular rough shark, showed that conditions like albinism or leucism do not necessarily compromise overall health. — Melissa Cristina Márquez, Forbes.com, 29 May 2026 See All Example Sentences for leucism

Word History

Etymology

borrowed from German Leucismus, from Greek leukós "clear, white" + German -ismus -ism — more at light entry 1

First Known Use

1878, in the meaning defined above

Time Traveler
The first known use of leucism was in 1878

Rhymes for leucism

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Browse Nearby Words

leucine
leucism
leucite
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Cite this Entry

“Leucism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/leucism. Accessed 10 Jul. 2026.

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