foster 1 of 2
fos·​ter ˈfȯ-stər 
ˈfä-
1
: having, relating to, or being the relationship between a foster parent and the child who the foster parent cares for
Although both girls lived with Ms. Ayala, Millison was the only one who was officially placed in her care as a foster child.—Ian Fisher
Twenty-three foster children now have a place to call home and family of their own following the Adoption Day at the Williamson County Courthouse in Marion on Friday.—Holly Kee
a foster mother/father
her new foster brother/sister
living with a foster family
foster parenting
the foster system
2
: being, relating to, or involved in a situation in which temporary care is given to an animal (such as one that is injured or awaiting adoption) in a household or similar setting
foster pets
a foster dog/cat/puppy/kitten
found foster placements for the animals
For the past year, Melbourne social impact strategy consultant Lee Crockford has been a foster dad to Romeo, an adorable Labrador puppy and future seeing eye dog.—Shannon Molloy

see also foster care, foster home

foster

2 of 2
fostered; fostering ˈfȯ-st(ə-)riŋ 
ˈfä-
; fosters
1
a
: to act as a foster parent to (a child)
The couple said they get … updates and pictures from all the children they've fostered.—Patrick Edrich
b
: to provide temporary care to (an animal that is injured, homeless, etc.) in a household or similar setting
… it's just her luck she'd find a partner who not only adores dogs but fosters them for a Sacramento animal shelter.—Gina Kim
2
: to promote the growth or development of : encourage
policies that foster cooperation
a lack of communication that fostered distrust
Grilling meat fosters the formation of potentially cancer-causing heterocyclic amines …—J. Raloff
The dead grass rotted in the warm water, releasing nutrients that fostered algae.—Carl Hiaasen
fosterer
ˈfȯ-stər-ər 
ˈfä-
noun
plural fosterers

Synonyms

Verb

Examples of foster in a Sentence

Verb Such conditions foster the spread of the disease. Would you consider fostering a child?
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Adjective
The entrepreneurial mindset and the experiences of foster youth share surprising parallels. —First Place For Youth, Forbes.com, 2 Apr. 2025 People can visit the shelter to adopt pets, for spay and neutering, vaccinations and other services, or to become part of the foster program. —Gary Warth, San Diego Union-Tribune, 31 Mar. 2025
Verb
This direct investment approach enables them to foster growth, influence strategic direction, and generate substantial returns. —Paul Westall, Forbes.com, 3 Apr. 2025 Through this initiative, M-DCPS continues its commitment to fostering a supportive, healthy, and successful learning environment for all students. —Unitedhealthcare, Miami Herald, 3 Apr. 2025 See All Example Sentences for foster

Word History

Etymology

Adjective and Verb

Middle English, from Old English fōstor-, from fōstor food, feeding; akin to Old English fōda food

First Known Use

Adjective

before the 12th century, in the meaning defined at sense 1

Verb

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of foster was before the 12th century

Phrases Containing foster

Rhymes for foster

Browse Nearby Words

foster
Foster
See all Nearby Words

Cite this Entry

“Foster.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/foster. Accessed 14 Apr. 2025.

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Kids Definition

foster

1 of 2 adjective
fos·​ter ˈfȯs-tər 
ˈfäs-
: giving, receiving, or sharing parental care even though not related by blood or legal ties
foster parent
foster child

foster

2 of 2 verb
fostered; fostering
1
: to give parental care to
2
: to help the growth or development of
fosterer noun

Legal Definition

foster

1 of 2 adjective
fos·​ter
: affording, receiving, or sharing nurture or parental care though not related by blood or legal relationships
a foster child
a foster parent

foster

2 of 2 transitive verb
fostered; fostering
: to give parental care to

Biographical Definition

Foster 1 of 2

biographical name (1)

Fos·​ter ˈfȯ-stər 
ˈfä-
Stephen Collins 1826–1864 American songwriter

Foster

2 of 2

biographical name (2)

William Z(ebulon) 1881–1961 American Communist

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