Definition of coal mine

coal minenoun

mỏ than

/ˈkəʊl maɪn//ˈkəʊl maɪn/

namespace

Related words and phrases

Idioms

a canary in a/the coal mine
something that gives you an early warning of danger
  • Among the species at risk is the silvery minnow, the river's equivalent of a canary in a coal mine.