half-sister

half-sister — noun

1. a female relative connected to you through just one birth parent — your mother o

1.nounB1
Definition

a female relative connected to you through just one birth parent — your mother or your father, not both

Example

Takeshi grew up with his half-sister Yuki, who shares his father but not his mother.

paternal half-sister: same father, different mother

When Anong visited her father's new family, she met her half-sister for the first time.

Common collocations
  • maternal half-sister
  • paternal half-sister
  • half-sister on ... side
  • half-sister from ... marriage
Synonyms
  • stepsister

    not a true synonym — a stepsister is unrelated by blood, whereas a half-sister shares one biological parent

Antonyms
  • sister

    a full sister shares both biological parents

Usage Note

Distinguish from stepsister: a half-sister is related by blood through one parent, whereas a stepsister has no blood relation — her parent married one of yours. Paternal half-sister (same father) and maternal half-sister (same mother) specify which side.

Common Mistakes

She is my stepsister — we share the same mother.
She is my half-sister
we share the same mother.' — 'Stepsister' means no blood relation; 'half-sister' means one biological parent in common.

Word family

Synonym discussion

Sense: noun/1

All three words describe a female sibling, but they differ in blood relation. A sister (or full sister) shares both biological parents with you. A half-sister shares one biological parent — either the same mother (maternal half-sister) or the same father (paternal half-sister) — but not both. A stepsister has no blood relation to you at all: her parent married your parent, making you step-siblings through marriage, not birth. For example: 'My sister Mia and I have the same mother and father.' 'My half-sister Sofia has my father but a different mother.' 'My stepsister Lucy joined our family when her dad married my mom.'

half-sister ↗stepsistersister ↗

Etymology

Old EnglishMiddle EnglishEnglish

The word half-sister comes from Old English 'half' (one of two equal parts) and 'sister' (a female sibling). It appeared in Middle English around the 1400s as 'halff-sister' to distinguish a sibling who shares only one parent from a full sibling who shares both.