sibling

sibling — noun

1. someone who shares a parent with another person — either a brother or a sister.

1.nounA2
Definition

someone who shares a parent with another person — either a brother or a sister.

Example

Élise has two younger siblings who still live at home with her parents.

younger / older + sibling

With three siblings, Femi learned to share and compromise by taking turns picking the TV show.

learned to + [verb] + by + V-ing (sharing strategy)

Common collocations
  • younger sibling
  • older sibling
  • youngest sibling
  • eldest sibling
  • sibling rivalry
Synonyms
  • brother

    specifically male; the most common term when gender is known

  • sister

    specifically female; the most common term when gender is known

  • half-sibling

    shares only one biological parent, not both

  • stepsibling

    not biologically related; related through a parent's remarriage

Antonyms

Grammar Patterns

sibling + of + person

possessive + sibling

Usage Note

Sibling is a gender-neutral alternative to brother or sister. Use it when the person's sex is unknown or unimportant to the context.

Common Mistakes

My sibling is a girl.
My younger sibling is a girl.
sibling does not indicate gender; if gender matters, add context or use 'brother' / 'sister'.
She is my sibling sister.
She is my sister.
sibling already includes the idea of sister; do not add both words together.

2. a company, product, organization, or other entity that belongs to the same group

2.nounB2
Definition

a company, product, organization, or other entity that belongs to the same group or family as another and is connected by a common origin or owner.

Example

The airline's sibling company runs the hotel chain under the same brand.

sibling company / sibling brand

Tuan works for a French firm and its sibling office in Tokyo.

Common collocations
  • sibling company
  • sibling brand
  • sibling organization
  • sibling species
  • sibling rivalry (in biology)
Synonyms
  • affiliate

    a company that is partially owned or controlled by another; more formal

  • subsidiary

    a company fully owned by a larger parent company; implies hierarchy, not equality

  • counterpart

    a person or thing that has a similar position or function in a different group

Antonyms

Grammar Patterns

sibling + noun (attributive)

the sibling of + noun phrase

Usage Note

This sense is most often used before a noun as an attributive modifier (sibling company, sibling brand, sibling species). It is common in business and academic contexts.

Word family

  • sib
    nounC2

Synonym discussion

Sense: noun/1

Brother and sister specify gender, while sibling is gender-neutral and covers both. Use sibling when the person's sex is unknown or irrelevant, or when referring to a mixed-gender group. Half-sibling refers to someone who shares only one biological parent — for example, a common mother but different fathers. Stepsiblings are not biologically related at all; they become family through a parent's remarriage. Unlike sibling, which implies a blood or legal parent relationship, stepsibling implies a blended family structure. For native-like usage: 'I have two brothers and a sister' sounds more natural in casual conversation than 'I have three siblings' if you know their genders.

brother ↗sister ↗half-siblingstepsibling

Common collocations

Nouns

Phrases

  • sibling rivalry
  • sibling relationship
  • sibling company
  • sibling brand
  • sibling species

Etymology

Old EnglishMiddle EnglishModern English

Sibling comes from Old English 'sibb', which meant 'kinship, relative, or peace'. The suffix '-ling' meant 'one belonging to' or 'one connected with'. Together they formed 'sibling' meaning 'one who is related by blood'. The word was common in Old English but mostly disappeared during the Middle English period. It was revived in the early 1900s by anthropologists and geneticists as a precise technical term, and later spread into everyday language.