[heyd] 
noun, verb, had⋅ed, had⋅ing.| 1. | Geology. the angle between a fault plane and the vertical, measured perpendicular to the strike of the fault; complement of the dip. |
| 2. | Mining. the inclination of a vein or seam from the vertical. |
| 3. | (of a fault, vein, or seam) to incline from a vertical position. |
| hade (hād) n. Geology The angle of inclination from the vertical of a vein, fault, or lode. [Origin unknown.] |