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fos·​ter ˈfȯ-stər How to pronounce foster (audio)
: 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
children in foster care
foster parenting
the foster system
: 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 home


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fostered; fostering ˈfȯ-st(ə-)riŋ How to pronounce foster (audio)
; fosters

transitive verb

: 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
: 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
: 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 noun
plural fosterers

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
Days after his birth, he was taken in by Lisa Barker Johnson, a foster mother in her 30s who lived in Zion, Ill., a working-class city halfway between Chicago and Milwaukee. Glenn Thrush Carlos Javier Ortiz, New York Times, 5 May 2024 Haddish and her four younger half-siblings ended up in foster care. Amy Kaufman, Los Angeles Times, 2 May 2024 See all Example Sentences for foster 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'foster.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Adjective and Verb

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

First Known Use


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


15th century, in the meaning defined at sense 1

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

Dictionary Entries Near foster

Cite this Entry

“Foster.” Dictionary, Merriam-Webster, Accessed 20 May. 2024.

Kids Definition


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


2 of 2 verb
fostered; fostering -t(ə-)riŋ How to pronounce foster (audio)
: to give parental care to
: to help the growth or development of
fosterer noun

Legal Definition


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


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 How to pronounce Foster (audio)
Stephen Collins 1826–1864 American songwriter


2 of 2

biographical name (2)

William Z(ebulon) 1881–1961 American Communist

More from Merriam-Webster on foster

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