What is "dormant window"

Dormancy \Dor"man*cy\, n. [From Dormant.] The state of being dormant; quiescence; abeyance.

It is by lying dormant a long time, or being . . . very rarely exercised, that arbitrary power steals upon a people.
--Burke.

2. (Her.) In a sleeping posture; as, a lion dormant; -- distinguished from couchant.

Dormant partner (Com.), a partner who takes no share in the active business of a company or partnership, but is entitled to a share of the profits, and subject to a share in losses; -- called also sleeping partner or silent partner.

Dormant window (Arch.), a dormer window. See Dormer.

Table dormant, a stationary table. [Obs.]
--Chaucer.

n. dormer-window