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 competition was open to all photographers who were invited to submit up to three images in one of nine categories covering mammals, reptiles, amphibians, birds and insects. —Joanne Shurvell, Forbes, 25 Sep. 2024

But reptiles deserve our sympathy — and conservation dollars — just as much as mammals, which may seem more charismatic. —Katie Hunt, CNN, 21 Sep. 2024

Take-off and landing kinetics of a free-ranging gliding mammal, the Malayan colugo (Galeopterus variegatus) iNaturalist. —Joshua Rapp Learn, Discover Magazine, 11 Sep. 2024

The chance encounter gave scientists a glimpse into this marine mammal’s deep-sea behaviors, sophisticated feeding strategies, preferred prey, and resting habits. —Laura Baisas, Popular Science, 4 Sep. 2024

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

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