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 relocation effort gained urgency after Marineland warned officials that it could be forced to euthanize the mammals if the export permits were not quickly approved. — Thao Nguyen, USA Today, 28 Aug. 2026

The result ravaged communities that rely on the ocean – fish, birds, marine mammals, and people who fish for their livelihoods throughout the eastern tropical Pacific. — Julia Cole, The Conversation, 27 Aug. 2026

The finalist images document the consequences of overfishing and bycatch, the impact of pollution on marine mammals and the killing of pilot whales in the Faroe Islands, a practice known as grindadráp. — Cecilia Rodriguez, Forbes.com, 23 Aug. 2026

The no-kill animal shelter will care for dogs, cats, and small companion mammals and will also include a low cost veterinary clinic, a pantry of pet food and supplies and public spaces. — Anna Ortiz, Chicago Tribune, 23 Aug. 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