In American architecture, fanlights were typical to the Adam, Colonial Revival, and Early Classical Revival styles. As was already mentioned, fanlights can be variously decorated; one very common version here is the spider light, in which the muntins and glazing are arranged to appear like a spider web.
Transoms can be made to open several ways; a pivot opening has the pivot in the middle of the window pane, so that it spins to become perpendicular to the frame; a hopper window pivots out from the bottom of the pane; and an awning window pivots out from the top of the pane.
"Window" comes from "wind holes," early openings which served principally to provide draft and emit smoke from internal fires.
The components of a window are:
head
jamb
sill
sash
frame
muntin
glazing
If in a wood-frame wall, the structure above the window is supported by a header; if in a masonry wall, the structure above the window is supported by a lintel.
And to complete the list of windows by opening type ... other windows can be fixed, single- or double-hung, casement, sliding or louver.
