supplement

1 of 3

noun (1)

sup·​ple·​ment ˈsə-plə-mənt 

1

a

: something that completes or makes an addition

b

: dietary supplement

2

: a part added to or issued as a continuation of a book or periodical to correct errors or make additions

3

: an angle or arc that when added to a given angle or arc equals 180°

supplement

2 of 3

verb

sup·​ple·​ment ˈsə-plə-ˌment 

supplemented; supplementing; supplements

transitive verb

: to add or serve as a supplement to

does odd jobs to supplement his income

supplementation

ˌsə-plə-ˌmen-ˈtā-shən 

-mən-

noun

supplementer

ˈsə-plə-ˌmen-tər 

noun

supplementation

3 of 3

noun (2)

sup·​ple·​men·​ta·​tion ˌsəplə(ˌ)men‧ˈtāshən 

-mən‧-

plural -s

: the act or process or an instance of supplementing

dietary supplementation

supplementation of state unemployment benefits

—R. A. Lester

Synonyms of supplement

Noun (1)

• increase
• boost
• addition
• gain

Examples of supplement in a Sentence

Noun (1)

the supplement to the encyclopedia

First-class accommodation is available for a supplement.

Verb

She began supplementing her diet with vitamins.

Recent Examples on the Web

Noun

For example, someone may sincerely believe a supplement, detox or alternative therapy helped when symptoms may have improved naturally or because of expectation alone. —Daryl Austin, USA Today, 18 June 2026

As a standalone oral supplement, it’s poorly absorbed, which is the reason clinics give for delivering it intravenously. —Allison Palmer, Charlotte Observer, 17 June 2026

Verb

But porters were able to supplement their wages with tips, which helped propel their families toward the middle class. —Nina Metz, Chicago Tribune, 17 June 2026

The plan isn’t supplementing individual initiative. —Nick Lichtenberg, Fortune, 17 June 2026

Word History

Etymology

Noun (1)

Middle English, borrowed from Anglo-French & Latin; Anglo-French, borrowed from Latin supplēmentum "something added to supply a deficiency or make up a whole, reinforcement," from supplēre "to fill up, complete, raise to its full complement" + -mentum -ment — more at supply entry 2

Verb and Noun (2)

derivative of supplement entry 1

First Known Use

Noun (1)

14th century, in the meaning defined at sense 1a

Verb

1659, in the meaning defined above

Phrases Containing supplement

• colour supplement
• dietary supplement

Kids Definition

supplement

1 of 2 noun

sup·​ple·​ment ˈsəp-lə-mənt 

1

: something that supplies what is needed or makes an addition

vitamin pills used as dietary supplements

2

: an arc or angle that when added to a given arc or angle equals 180 degrees

supplemental

ˌsəp-lə-ˈment-ᵊl

adjective

supplement

2 of 2 verb

sup·​ple·​ment ˈsəp-lə-ˌment 

: to add to

supplement their incomes by doing odd jobs

supplementation

ˌsəp-lə-ˌmen-ˈtā-shən 

-mən-

noun

Medical Definition

supplement

1 of 2 noun

sup·​ple·​ment ˈsəp-lə-mənt 

1

: something that completes or makes an addition

2

: dietary supplement

supplement

2 of 2 transitive verb

sup·​ple·​ment ˈsəp-lə-ˌment 

: to add a supplement to : serve as a supplement for

utilizes … surgery to supplement the traditional treatment

—Therapeutic Notes

supplementation

ˌsəp-lə-ˌmen-ˈtā-shən, -mən- 

noun