Depth

1. The quality of being deep; deepness; perpendicular measurement downward from the surface, or horizontal measurement backward from the front; as, the depth of a river; the depth of a body of troops.
2. Profoundness; extent or degree of intensity; abundance; completeness; as, depth of knowledge, or color.
3. Lowness; as, depth of sound.
4. That which is deep; a deep, or the deepest, part or place; the deep; the middle part; as, the depth of night, or of winter.
5. (Logic) The number of simple elements which an abstract conception or notion includes; the comprehension or content.
6. (Horology) A pair of toothed wheels which work together.
7. (Aëronautics) The perpendicular distance from the chord to the farthest point of an arched surface.
8. (Computers) the maximum number of times a type of procedure is reiteratively called before the last call is exited; -- of subroutines or procedures which are reentrant; -- used of call stacks.
Depth of a sail (Naut.),
the extent of a square sail from the head rope to the foot rope; the length of the after leach of a staysail or boom sail; -- commonly called the drop of a sail.