indented

1. Cut in the edge into points or inequalities, like teeth; jagged; notched; stamped in; dented on the surface.

2. Having an uneven, irregular border; sinuous; undulating. Milton. Shak.

3. (Her.) Notched like the part of a saw consisting of the teeth; serrated; as, an indented border or ordinary.

4. Bound out by an indenture; apprenticed; indentured; as, an indented servant.

5. (Zoöl.) Notched along the margin with a different color, as the feathers of some birds.

Indented line (Fort.), a line with alternate long and short faces, with salient and receding angles, each face giving a flanking fire along the front of the next.

adjective

Curving inward: cavernous, concave, hollow, sunken. See convex/concave.

The adjective has 2 meanings:

Meaning #1: having repeated square indentations like those in a battlement
  Synonyms: embattled, crenelated, crenelate, crenellated, crenellate

Meaning #2: having the central portion lower than the margin
  Synonym: depressed