Used to denote (1) the grave or the abyss (Romans 10:7; Luke 8:31); (2) the deepest part of the sea (Psalm 69:15); (3) the chaos mentioned in Genesis 1:2; (4) the bottomless pit, hell (Revelation 9:1, 2; 11:7; 20:13).

Noah Webster's New International Dictionary of the English Language

1. (superl.) Extending far below the surface; of great perpendicular dimension (measured from the surface downward, and distinguished from high, which is measured upward); far to the bottom; having a certain depth; as, a deep sea.

2. (superl.) Extending far back from the front or outer part; of great horizontal dimension (measured backward from the front or nearer part, mouth, etc.); as, a deep cave or recess or wound; a gallery ten seats deep; a company of soldiers six files deep.

3. (superl.) Low in situation; lying far below the general surface; as, a deep valley.

4. (superl.) Hard to penetrate or comprehend; profound; -- opposed to shallow or superficial; intricate; mysterious; not obvious; obscure; as, a deep subject or plot.

5. (superl.) of penetrating or far-reaching intellect; not superficial; thoroughly skilled; sagacious; cunning.

6. (superl.) Profound; thorough; complete; unmixed; intense; heavy; heartfelt; as, deep distress; deep melancholy; deep horror.

7. (superl.) Strongly colored; dark; intense; not light or thin; as, deep blue or crimson.

8. (superl.) of low tone; full-toned; not high or sharp; grave; heavy.

9. (superl.) Muddy; boggy; sandy; -- said of roads.

10. (adv.) To a great depth; with depth; far down; profoundly; deeply.

11. (n.) That which is deep, especially deep water, as the sea or ocean; an abyss; a great depth.

12. (n.) That which is profound, not easily fathomed, or incomprehensible; a moral or spiritual depth or abyss.