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

Anyone seeing a manatee or other marine mammal in distress is asked to call the Florida Fish and Wildlife Conservation Commission’s hotline at 1-888-404-3922. —David Goodhue, Miami Herald, 6 May 2026

Bison are the national mammal of the United States and are seen as a symbol of the West. —Julia Gomez, USA Today, 6 May 2026

Sloths are unable to regulate their body temperature as well as other mammals and do best in the 68-to-85 degree Fahrenheit (20 to 30 degrees Celsius) range. —ABC News, 4 May 2026

Nolan mentioned teaching his parents about tenrecs, a mammal that resembles hedgehogs, after the Madagascar-native animal visited Nolan’s classroom. —Lina Ruiz may 4, Fort Worth Star-Telegram, 4 May 2026

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