step-sister

step-sister — noun

1. a girl or woman who becomes your sister because one of your parents marries her

1.nounB1
Definition

a girl or woman who becomes your sister because one of your parents marries her parent, not because you share a biological parent

Example

After the ceremony, Layla and Sana became step-sisters and shared one bedroom.

become step-sisters after a parent's marriage

Felix asked his step-sister to bring his gym shoes after practice.

possessive + step-sister

Common collocations
  • older step-sister
  • younger step-sister
  • become step-sisters
  • live with a step-sister
Synonyms
  • stepsister

    same meaning in the more common one-word spelling

  • stepsibling

    broader and gender-neutral, so it is less specific than step-sister

Grammar Patterns

[possessive] + step-sister

become + step-sisters

Usage Note

Usually names a sister relationship created when parents marry or form one household. The one-word spelling 'stepsister' is more common in current English. Distinguish it from 'half-sister', who shares one biological parent with you.

Common Mistakes

Mina is my step-sister because we have the same mother.
Mina is my half-sister because we share one parent.
a step-sister joins the family through a parent's marriage, not through birth.
My adopted sister is also my step-sister.
My adopted sister joined our family through adoption, not as a step-sister.
'step-sister' specifically refers to a sibling relationship created by remarriage.

Word family

Synonym discussion

Sense: noun/1

Step-sister and stepsister mean the same thing: a sister in a blended family whose connection comes from a parent's marriage, not from birth. The difference is mainly spelling, with the closed form stepsister now more common. Half-sister is different because you share one biological parent, so it describes blood relation rather than remarriage. Stepsibling is broader and can refer to either a brother or a sister, which is useful when gender does not matter. Compare: 'Sana became my step-sister when our parents married,' 'Mina is my half-sister because we share a mother,' and 'Each child met a new stepsibling after the wedding.'

step-sister ↗stepsister ↗half-sister ↗stepsibling ↗

Common collocations

Nouns

  • step-sister relationship
  • step-sister bond

Phrases

  • older step-sister
  • younger step-sister
  • become step-sisters

Prepositions

Etymology

Old EnglishEnglish

This family word joins step- with sister. In older English, step- came from Old English steop- and was used for family relationships formed after remarriage. Sister comes from Old English sweostor. Together they describe a sister in a newly joined family rather than a sister related by birth.

First known use

15th century

15th century, in the meaning defined above