Definition of mum and dad in English:

mum and dad

(also mums and dads)

adjective

Australian, NZ
informal
  • Attributive Designating a business venture, especially a small shop, of a type often run by a married couple. Later also: denoting any pastime, activity, etc., typically associated with or regarded as appealing to married couples; specifically designating or relating to an investment opportunity designed for small-scale investors.

Origin

1960s; earliest use found in The Courier-Mail. From mum + and + dad.

Pronunciation

mum and dad

/ˌmʌm ən ˈdad/