foster-sister

5.1

A girl or woman raised by your family who is not related by blood

noun
/ˈfɔstər ˈsɪstər/

: hermana de crianza

Every summer, my foster-sister and I would visit our grandparents in the countryside.

Examples

Although we are not related by blood, I consider my foster-sister a true part of my family.
My foster-sister is coming to visit this weekend.
After her parents adopted Maria, she became my foster-sister and we grew up together.
She has always considered her foster-sister as her real sister.
Although we are not related by blood, I consider my foster-sister a true part of my family.
My foster-sister is coming to visit this weekend.
After her parents adopted Maria, she became my foster-sister and we grew up together.

Synonyms

foster sister

vsfoster-sister

1 3.5

A girl or woman not related by birth who your parents raise as part of the family

has identical meaning but is written as one hyphenated form

Surface Forms

foster-sister singular

foster-sisters plural

Morphology

foster-sister = foster + sister (transparent) = foster + sister

The meaning is a straightforward combination of 'foster' (not biological, raised by caregivers) + 'sister' (female sibling), which B1 learners can infer if they know both components.

Etymology

Foster-sister combines foster (an old word meaning 'to feed' or 'to raise') and sister ('female sibling'), so a foster-sister is a girl who is raised in your family and treated like a sister even if she is not related by blood.