foster

1 of 2

adjective

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

verb

fostered; fostering ˈfȯ-st(ə-)riŋ 

ˈfä-

; fosters

transitive verb

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

• promote
• encourage
• cultivate
• nurture

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

Adjective

Lockhart made an indelible mark playing Ruth Martin, the foster mother of John Provost’s character, Timmy, and his collie Lassie, on the series Lassie beginning in 1958. —Althea Legaspi, Rolling Stone, 25 Oct. 2025

Yarsh, 34, rescued Chimney as a foster fail in May 2025, and since then he’s settled into his forever home incredibly well. —Alyce Collins, MSNBC Newsweek, 22 Oct. 2025

Verb

Charlie had been abandoned and then rescued and fostered by a man in Jacksonville. —Jack Beresford, MSNBC Newsweek, 25 Oct. 2025

Soon, the newcomers built the town's iconic brick buildings along the Missouri, established wineries, and fostered a deep sense of community that can still be seen and felt, nearly two centuries later. —Erika Ebsworth-Goold, Travel + Leisure, 25 Oct. 2025

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

Phrases Containing foster

• foster brother/sister
• foster care
• foster child
• foster children
• foster dog/cat/puppy/kitten
• foster family
• foster home
• foster mother/father
• foster parent
• foster parenting
• foster pets
• foster system

Rhymes for foster

• coster
• roster
• zoster
• exhauster
• imposter
• impostor

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 -t(ə-)riŋ 

1

: to give parental care to

2

: to help the growth or development of

fosterer

-tər-ər 

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