supplement

1 of 2

noun

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 2

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

Synonyms

Noun

• increase
• boost
• addition
• gain

Examples of supplement in a Sentence

Noun

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

Experts like Ford say the key is to use Social Security as a supplement, not a replacement for a paycheck. —David McMillin, CNBC, 24 Oct. 2025

However, more research is needed to understand the long-term effects of collagen supplements on various conditions. —Devineé Lingo, Health, 23 Oct. 2025

Verb

Her crew of 50 cameramen was supplemented by an order from the government that all of the weekly German news shows were to make their footage available to her. —Sally Jenkins, The Atlantic, 27 Oct. 2025

As a result, today’s businesses are seeking out the top CRM tools to supplement their growth. —Nia Bowers, USA Today, 27 Oct. 2025

Word History

Etymology

Noun

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

derivative of supplement entry 1

First Known Use

Noun

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