mammal

noun

mam·​mal ˈma-məl How to pronounce mammal (audio)
: any of a class (Mammalia) of warm-blooded higher vertebrates (such as placentals, marsupials, or monotremes) that nourish their young with milk secreted by mammary glands, have the skin usually more or less covered with hair, and include humans
mammalian adjective or noun
mammal-like adjective
or less commonly mammallike
mammal-like behavior
mammallike reptiles

Examples of mammal in a Sentence

Human beings, dogs, and cats are all mammals.
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 brackish waters are ideal for bald cypress trees that serve as habitat for countless birds and an array of amphibians, reptiles and mammals. Cecilia Rodriguez, Forbes, 24 Feb. 2025 Caper and Katherine are northern tree shrews, small mammals native to Southeast Asian forests who spend their days foraging for fruit and insects, according to Potter Park Zoo. Rhiannon Saegert, Miami Herald, 20 Feb. 2025 The 360-acre preserve is home to a variety of mammals, including bobcats, raccoons, armadillos, opossums, rabbits and foxes. Joe Rassel, Orlando Sentinel, 19 Feb. 2025 The results — covering the fall of dinosaurs and the rise of mammals — demonstrate how certain species play a major role in influencing the world around them as ecosystem engineers. Jack Knudson, Discover Magazine, 18 Feb. 2025 See All Example Sentences for mammal

Word History

Etymology

from base of New Latin Mammalia (Linnaeus), class name, noun derivative from neuter plural of mammālis, from Latin mamma "breast, udder" + -ālis -al entry 1 — more at mamma entry 1

First Known Use

1811, in the meaning defined above

Time Traveler
The first known use of mammal was in 1811

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Cite this Entry

“Mammal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mammal. Accessed 27 Feb. 2025.

Kids Definition

mammal

noun
mam·​mal ˈmam-əl How to pronounce mammal (audio)
: any of a class of warm-blooded vertebrates that include human beings and all other animals that nourish their young with milk produced by mammary glands and have the skin usually more or less covered with hair

Medical Definition

mammal

noun
mam·​mal ˈmam-əl How to pronounce mammal (audio)
: any of the higher vertebrate animals comprising the class Mammalia
mammalian adjective or noun

More from Merriam-Webster on mammal

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