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

Research suggests the body’s circadian rhythm—the internal clock that regulates sleep, hormones, and metabolism—is partly influenced by meal timing. — Trista Chan, HEALTH, 17 Aug. 2026

Meetings adopted that metabolism — they were scheduled every week or two at the Government Center. — Peter St Onge, Charlotte Observer, 17 Aug. 2026

Females prefer these waters to reproduce, and during the summer male rays have a higher metabolism that drives them to seek out food in the invertebrates along the shore, Lowe said. — ABC News, 13 Aug. 2026

What these early animals released back into the ocean were mostly just chemical byproducts of their cells’ metabolism, not nutrients most other animals could use. — ArsTechnica, 12 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