metabolism

noun

me·​tab·​o·​lism mə-ˈta-bə-ˌli-zəm 

1

a

: the sum of the processes in the buildup and destruction of protoplasm

specifically : the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated (see assimilate entry 1 sense 1b)

Regular exercise can help to increase your metabolism.

b

: the sum of the processes by which a particular substance is handled in the living body

c

: the sum of the metabolic activities taking place in a particular environment

the metabolism of a lake

2

: metamorphosis sense 2

—usually used in combination

holometabolism

Examples of metabolism in a Sentence

studying the metabolisms of various organisms

Recent Examples on the Web

Many occur naturally in the body and act as chemical messengers, influencing metabolism, inflammation, reproduction and other physiological processes. — Robert Pearl, Forbes.com, 10 Aug. 2026

It's also involved in metabolism, bone health, muscle mass, red blood cell production and brain function. — Will Stone, NPR, 10 Aug. 2026

While the peptide’s risks and side effects are few, and its effects on mouse metabolism compelling, no one knows how long-term use affects humans yet, or what formula or dosage would be most effective. — Los Angeles Times, 6 Aug. 2026

Firefighters have major health issues, Masoud said, and that the purpose of the study is to identify how the environments and conditions they’re exposed to affect their body, metabolism and muscles. — Cam'ron Hardy, Chicago Tribune, 6 Aug. 2026

Word History

Etymology

metabol(ic) + -ism, after French métabolisme or German Metabolismus

First Known Use

1878, in the meaning defined at sense 1a

Phrases Containing metabolism

• basal metabolism

Rhymes for metabolism

• activism
• albinism
• altruism
• aneurism
• animism
• aphorism
• atomism
• barbarism
• bolshevism
• botulism
• brahmanism
• calvinism

Kids Definition

metabolism

noun

me·​tab·​o·​lism mə-ˈtab-ə-ˌliz-əm 

1

: the processes essential for life by which the complex substances in the cells of living things are built up or broken down

2

: the processes by which a particular substance (as iodine) is handled in the living body

Medical Definition

metabolism

noun

me·​tab·​o·​lism mə-ˈtab-ə-ˌliz-əm 

1

a

: the sum of the processes in the buildup and destruction of protoplasm

specifically : the chemical changes in living cells by which energy is provided for vital processes and activities and new material is assimilated

methods of determining body and tissue metabolism

—Bulletin of the University of Kentucky

see anabolism, catabolism

b

: the sum of the processes by which a particular substance is handled (as by assimilation and incorporation or by detoxification and excretion) in the living body

the metabolism of iodine in the thyroid

2

: metamorphosis sense 2

—usually used in combination

holometabolism