A female parent. The informal word is 'mum' (British English) or 'mom' (American English).

Countable noun. Plural: mothers. Informal equivalents: mum (UK), mom (US), mummy, mama. Common collocations: mother tongue (your first language), grandmother, mother-in-law, motherly.

Mother's Day (called Mothering Sunday in the UK) is celebrated on the fourth Sunday of Lent in Britain, and in May in the US and Australia. 'Mother tongue' means the first language you learned as a child. 'Mother Nature' refers to the natural world personified as a woman.