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

While many consider the mammal a nuisance for raiding garbage cans and damaging property, raccoons can also carry diseases, and they probably shouldn't be kept as housepets. —Marina Johnson, Louisville Courier Journal, 3 Oct. 2025

For mammals, that is typically the females. —Laura Baisas, Popular Science, 1 Oct. 2025

In 2013, Nature Communications published a study estimating that, in the United States, cats kill somewhere between one and four billion birds each year, and perhaps five times as many small mammals. —Rebecca Van Laer september 30, Literary Hub, 30 Sep. 2025

Each summer, a high concentration of bears congregate along the Brooks River as salmon migrate upstream to spawn, creating easy pickings for the mammals who need to pack on the fat ahead of hibernation. —Lydia Mansel, Travel + Leisure, 27 Sep. 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