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 brackish waters are ideal for bald cypress trees that serve as habitat for countless birds and an array of amphibians, reptiles and mammals. —Cecilia Rodriguez, Forbes, 24 Feb. 2025

Caper and Katherine are northern tree shrews, small mammals native to Southeast Asian forests who spend their days foraging for fruit and insects, according to Potter Park Zoo. —Rhiannon Saegert, Miami Herald, 20 Feb. 2025

The 360-acre preserve is home to a variety of mammals, including bobcats, raccoons, armadillos, opossums, rabbits and foxes. —Joe Rassel, Orlando Sentinel, 19 Feb. 2025

The results — covering the fall of dinosaurs and the rise of mammals — demonstrate how certain species play a major role in influencing the world around them as ecosystem engineers. —Jack Knudson, Discover Magazine, 18 Feb. 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