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

Your body follows a 24-hour biological clock known as a circadian rhythm, which plays a significant role in your hormonal regulation, metabolism, body temperature, and brain function. —Rikkilynn Shields Hannigan, Health, 14 Jan. 2026

Sleep Quality and Stress Level Sleep and stress can impact hormones that influence your metabolism and ability to lose weight. —Sara Hoffman, Verywell Health, 13 Jan. 2026

The third hormone, glucagon, speeds up metabolism and helps the body break down fat cells for energy. —Angelica Stabile, FOXNews.com, 12 Jan. 2026

Nature has its own energy; the flower embodies its own cellular metabolism, its particular texture and life cycle. —Dan Turello, New Yorker, 10 Jan. 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
• ageism
• albinism
• altruism
• aneurism
• animism
• aphorism
• atomism
• barbarism
• bolshevism
• botulism
• brahmanism

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