in-law

in-law — noun

1. someone who becomes a member of your family because of a marriage, rather than t

1.nounB1
Definition

someone who becomes a member of your family because of a marriage, rather than through blood. The word is most often used in the plural form 'in-laws' to refer to all such relatives together — for instance, your spouse's parents, siblings, or their husbands and wives.

Example

Tomás gets along with his in-laws and plays chess with his father-in-law every Sunday.

collocation: get along with one's in-laws

After Priya's wedding, her in-laws threw a big party to welcome her to the family.

Common collocations
  • get along with one's in-laws
  • meet the in-laws
  • visit the in-laws
  • both sets of in-laws
  • in-laws' house
  • live with one's in-laws
Synonyms
Antonyms

Grammar Patterns

in-laws as plural noun referring to the group

Usage Note

Rarely used in the singular form on its own; the plural 'in-laws' is far more common in everyday speech. The singular form usually appears as part of a compound noun such as 'mother-in-law' or 'brother-in-law'.

Common Mistakes

I am going to visit my in-law's house.' (apostrophe placement confusion).
I am going to visit my in-laws' house.
the plural possessive requires the apostrophe after the -s.
She is an in-law of mine' (grammatically correct but awkward; most speakers use the compound).
She is my sister-in-law.
use the specific compound form when referring to one person.

Word family

  • in-laws
    nounB1
  • mother-in-law
    nounA2
  • father-in-law
    nounA2
  • brother-in-law
    nounB1
  • sister-in-law
    nounB1
  • son-in-law
    nounB1
  • daughter-in-law
    nounB1

Synonym discussion

Sense: noun/1

'In-laws' specifically refers to the relatives you gain through your spouse — their parents, siblings, and siblings' spouses. 'Relative by marriage' is a more formal and literal description that covers the same group but sounds less natural in casual conversation. 'Extended family' is much broader: it includes blood relatives beyond the nuclear family (cousins, aunts, uncles) as well as in-laws. 'Kin' is an older, more literary term that can refer to both blood and marriage relations; it is rarely used in everyday speech. For example: 'My in-laws are staying with us this weekend' clearly means your spouse's family. 'My extended family is spread across three countries' could include both blood relatives and in-laws. 'He is my kin by marriage' sounds legal or old-fashioned, not conversational.

relative by marriageextended familykin

Common collocations

Nouns

  • in-laws' house
  • in-laws' visit
  • in-laws' opinion
  • in-laws' expectations
  • in-laws' relationship

Phrases

  • meet the in-laws
  • visit the in-laws
  • live with one's in-laws
  • get along with one's in-laws
  • both sets of in-laws
  • stay with the in-laws

Etymology

English

The word 'in-law' is a shortening of marriage-relation compound nouns like 'mother-in-law', which first appeared in the 1400s. The 'in law' part means 'by operation of law' — the relationship is created through the legal institution of marriage, not through blood. The standalone form 'in-law' (referring to any relative by marriage) became common in the 1900s as a convenient way to refer to the group collectively.