Strike

Strike, a term borrowed by geologists from the German streichen, 'to extend,' and adopted with the technical meaning it has in that language. It is applied to the direction of the outcrop of a stratum—the line which it makes when it appears at the surface of the earth. This line is always at right angles to the dip of the bed. The angle of dip and the direction of strike are determined by a clinometer and compass. A perfectly horizontal stratum can have neither dip nor strike.