Having a hole, depression, or groove on the surface; depressed below the surrounding surface, sunken, indented; excavated, concave.

(a) Excavated, dug out or up; †(b) Sunken, depressed, hollow.

Hollow, concave; deep, low. In quot. 1536 how tide = low tide.

Deeply set.

Lowered, sunken, or low in position; lower than the general surface: opposed to elevated.

= depressed, adj.

At a lower level than the surrounding area. Designating work produced in various crafts in which depression below the level of a surrounding surface…

Set in a recess; set back or away. Frequently with reference to architectural or ornamental features. Also figurative: withdrawn.

Of a person's eyes, cheeks, etc.: having the appearance of having sunk into the face; unusually hollow or deeply set, esp. because of tiredness…

That resembles a niche.

Of a physical (esp. a facial) feature: sloping backwards, receding.

Astricted to a mill; = thirl, adj.