Definition of ma-in-law in US English:

ma-in-law

noun

British
informal
  • Mother-in-law.

Origin

Late 19th century; earliest use found in Davenport (Iowa) Weekly Leader. From ma + -in-law, after mother-in-law.

Pronunciation

ma-in-law

/ˈmɑː(r)ɪnlɔː/