1. The general disposition, attitude, arrangement, or relative position of the rock masses of an area; the sum total of the structural features of an area, consequent upon such deformational processes as faulting, folding, and igneous intrusion. 2. Any physical arrangement of rocks (such as an anticline, fault, or dome) that may involve the accumulation of oil or gas. 3. A subsurface area characterized by folding and/or faulting. 4. Seismic anomaly, usually a closed high.