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

Pronghorn can reach a speed off 60 mph and are the fastest land mammals in North America. —Gary Stoller, Forbes.com, 11 June 2025

Designed to coincide with Pride Month and the 80th anniversary of these odd Finnish mammals(?), the exhibit and its attendant public programming probably represent the largest gathering of Moomins to ever occur stateside. —Brittany Allen, Literary Hub, 5 June 2025

The sea mammals can live up to 90 years, and reach sizes of 60 feet in length and 40 tons, the National Oceanic and Atmospheric Administration says. —Mark Price, Miami Herald, 2 June 2025

Scientists used remote sensing and field data to track the mammals, by combining snow track counts of wolverines with national forest inventory data based on satellite images and field measurements. —Julia Jacobo, ABC News, 30 May 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