Emily Dickinson Lexicon

COUN'TER-MINE, n. [counter and mine.]

1. In military affairs, a well and gallery sunk in the earth and running under ground, in search of the enemy's mine, or till it meets it to defeat its effect. – Military Dict.
2. Means of opposition or counteraction. – Sidney.
3. A stratagem or project to frustrate any contrivance. – L'Estrange.