Definition of countermine in US English:

countermine

noun

Military
  • An excavation dug to intercept another dug by an enemy.

    • ‘Here, the engineer is Hamlet, who is going to place some explosives in a countermine, one yard underneath that of his ‘excellent good friends’.’
    • ‘Mining, with gunpowder now replacing the pig-fat of yesteryear, might accelerate the process, but a wily defender would have prepared countermine galleries of his own, and a wet ditch presented particular problems.’
    • ‘A mine dug through the solid rock below the castle was intercepted by a countermine, bringing the mining to an end.’
    • ‘A countermine was successful when an enemy tunnel was intercepted.’

verb

[with object]Military
  • Dig a countermine against.

    • ‘Few aspects of ancient warfare are more conducive to archaeological research than siege mining and countermining.’
    • ‘By countermining at these points, the Barcaeans broke into the enemy's works and slew the men they found there.’
    • ‘Mining operations and countermining operations have been part of America's wars since World War II.’
    • ‘Another 20 unknown contacts were countermined in harbours as the team responded to USN unmanned vehicle or marine mammal searches.’

Pronunciation

countermine

/ˈkoun(t)ərˌmīn//ˈkaʊn(t)ərˌmaɪn/