Countersign :: Countersign (v. t.) To sign on the opposite side of (an instrument or writing); hence, to sign in addition to the signature of a principal or superior, in order to attest the authenticity of a writing..
Countersign :: Countersign (a.) The signature of a secretary or other officer to a writing signed by a principal or superior, to attest its authenticity..
Countersign :: Countersign (a.) A private signal, word, or phrase, which must be given in order to pass a sentry; a watchword..
Countersink :: Countersink (v. t.) To chamfer or form a depression around the top of (a hole in wood, metal, etc.) for the reception of the head of a screw or bolt below the surface, either wholly or in part; as, to countersink a hole for a screw..
Countersink :: Countersink (v. t.) To cause to sink even with or below the surface; as, to countersink a screw or bolt into woodwork..
Countersink :: Countersink (n.) An enlargement of the upper part of a hole, forming a cavity or depression for receiving the head of a screw or bolt..
Countersink :: Countersink (n.) A drill or cutting tool for countersinking holes.