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

Its more than 440 vertebrate species include 39 fishes, 64 reptiles, 50 mammals and 235 birds (which make the Okefenokee a prime bird watching venue). — Charles Seabrook, AJC.com, 25 July 2026

But could these large marine mammals also play with their prey just for fun? — Matthew Glasser, ABC News, 23 July 2026

Most mammals—but not humans—contain alpha gal, so someone with alpha-gal syndrome will likely have an allergic reaction to consuming meat from cows, pigs, lambs, goats, and deer. — Alice Park, Time, 23 July 2026

However, if any mammal can transcend the limitations of a disability, raccoon would be at the top of my list. — Kelly Lambert, The Conversation, 23 July 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