mammal

noun

mam·​mal ˈma-məl 

: 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

mə-ˈmā-lē-ən 

ma-

adjective or noun

mammal-like

ˈma-məl-ˌlīk 

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

The marine mammals then swam alongside their vessel for around an hour. —Brendan Rascius, Miami Herald, 19 Mar. 2025

Instructors will focus on coastal, estuarine, and uplands habitats; coastal plants; and marine invertebrates, birds, mammals, reptiles, and fish. —Joe Rassel, Orlando Sentinel, 19 Mar. 2025

Related article Bird flu variant found in Nevada cows shows signs of adaptation to mammals OPPR also coordinated with the US Department of Veterans Affairs, the Federal Emergency Management Agency and partners from industry to maintain therapeutics in the Strategic National Stockpile. —Brenda Goodman, CNN, 17 Mar. 2025

In addition to North Carolina’s red-wolf crossings, the program has awarded grants for nearly three dozen projects — some of which will aid imperiled species such as ocelots and desert tortoises, many more that will seek to avert dangerous crashes with large mammals like deer, elk, and moose. —Ben Goldfarb, Vox, 14 Mar. 2025

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

Rhymes for mammal

• camel
• hamel
• hamil
• trammel
• enamel
• glutamyl

Kids Definition

mammal

noun

mam·​mal ˈmam-əl 

: 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 

: any of the higher vertebrate animals comprising the class Mammalia

mammalian

mə-ˈmā-lē-ən, ma- 

adjective or noun