mother-in-law
Pluralmothers-in-law
- 1A person's mother by marriage: the mother of one's husband or wife.
She invited her mother-in-law to help plan the wedding.
Relations between the new bride and her mother-in-law gradually warmed over the years.
Note
The kinship sense the others borrow from: Middle English moder in lawe, simply mother plus -in-law. The King James Bible of 1611 writes it open, "the daughter in law against her mother in law"; modern spelling joins it with hyphens. The plural marks the head noun, mothers-in-law. Mother-in-laws is a colloquial, nonstandard plural, best kept out of careful writing.
- 2A small, self-contained living unit within or attached to a single-family house, typically intended for a relative.
They added a mother-in-law above the garage for his aging father.
The listing advertised a finished basement with a separate mother-in-law.
Similarannex
Note
A clipped name. The full form is mother-in-law apartment, and in everyday use the second noun falls away, leaving the kinship phrase to name the space itself. Context does the work of telling them apart: a mother-in-law with its own entrance is a living unit, not the spouse's mother. Spelled out in full, the compound keeps its hyphens before apartment.
- 3A Chicago specialty consisting of a corn tamale served inside a hot dog bun and topped with chili.
He ordered a mother-in-law and a cold soda after his shift.
Nothing beats a mother-in-law from the stand on the corner.
- 4A spicy Caribbean sauce made with peppers, carrots, onions, lime juice, and other ingredients.
She spooned mother-in-law over the grilled fish.
The recipe calls for a generous splash of mother-in-law.
Note
Unlike the other senses, the sauce is a mass noun. You add some mother-in-law or a spoonful of mother-in-law, never a mother-in-law or mothers-in-law. That grammar is the quickest way to tell it apart in a sentence: with an article in front, the word almost always means a person, a room or a sandwich instead.
Less common meaning
- 5A stepmother; the woman married to one's parent who is not one's biological mother.
The widower's children resented their mother-in-law, who had taken their late mother's place.
Her diary complained bitterly of the mother-in-law her father had brought home.
Similarstepmother
Note
An older stretch of the kinship term, now dated. Here -in-law covers a mother gained through a parent's marriage rather than through one's own. Readers of older texts may meet it. In modern writing it would almost certainly be misread as the spouse's mother, so stepmother is the safe word whenever the relationship needs to be clear.
Practice
Can you tell the meanings of mother-in-law apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.
Origin
From Middle English "moder in lawe," equivalent to "mother" combined with the suffix "-in-law."