Sliding

A window that opens by sliding horizontally.

Double Sliding

A window that has two opening panels that slide horizontally.

Single Hung

One sash in the window frame is operable and moves up and down.

Double Hung

Both sashes in the window frame are operable and move up and down.

Louvre

Composed of parallel blades set in a frame, joined on a track so they tilt open and shut in unison.