1. The signature of a secretary or other officer to a writing signed by a principal or superior, to attest its authenticity.
2. (Mil.)
Defn: A private signal, word, or phrase, which must be given in order to pass a sentry; a watchword.
COUNTERSINK Coun"ter*sink` (koun"tr-sk`; 277), v. t. [imp. & p. p. Countersunk (- s; p. pr. & vb. n. Countersinking.]
1. 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.
2. To cause to sink even with or below the surface; as, to countersink a screw or bolt into woodwork.
COUNTERSINK
Coun"ter*sink`, n.
1. An enlargement of the upper part of a hole, forming a cavity or depression for receiving the head of a screw or bolt.
Note: In the United States a flaring cavity formed by chamfering the edges of a round hole is called a countersink, while a cylindrical flat-bottomed enlargement of the mouth of the hole is usually called a conterbore.
2. A drill or cutting tool for countersinking holes.