Legs
Rear Curtains
Border
Types of Theater Curtains
Front Curtain
This interactive guide will help explain the basics of theater curtain terminology.
Cyclorama
Valance
Types of Theater Curtains
Tableau
Front Curtain, also House Curtain, Main Curtain,  Main Act Curtain, or Proscenium Curtain.This curtain is used to define the stage location to the arriving audience. It is often the curtain closest to the audience and may also perform the function of an "Act Curtain." 
Traveler
Venetian
Austrian
Front Curtain Traveler Style
The most common main act curtain is the draw or traveler curtain, which is made of two bi-parting sections. These sections are placed on two overlapping sections of track, and each half can be drawn from the center to the opposite side of the stage.
The Venetian Curtain or Contour Curtain is a specialty main act curtain that is raised by vertical lift lines which are individually adjustable, making it possible to open the view of the stage in various contours.
Front Curtain Venetian Style
The Austrian Curtain is a specialty main act curtain that is raised by multiple vertical lift lines where the amount of lift on each draw line is equal. It is sewn with vertical and horizontal fullness. This creates a series of horizontal swaging pleats. Contoured effects can be achieved by varying the speed of the draw lines as the curtain is being raised.
Front Curtain Austrian Style
The Tableau, or Tab Curtain is a specialty main act curtain that has two panels, sewn flat or with fullness, that is raised by diagonal lifting on the two on-stage lower corners towards the upper off-stage sides.
Front Curtain Tableau Style
A border curtain used to define the top limit of the stage and to mask or hide lights and unused scenery and curtains. The valance is usually a special border associated with the Front Curtain. May be permanently fixed within the proscenium arch.
A curtain used to define the top limit of the stage and to mask or hide lights and unused scenery and curtains. 
RearCurtain
Rear Traveler or Back Curtain, Rear Curtain. A 2-piece bi-parting curtain located up stage.
RearCurtain
Leg
A curtain used to define the side limit of the stage and to mask or hide actors, lights, and unused scenery in the off stage area (wings).
Cyclorama or Cyc. (1) Curtain at the rear of the performance area used to represent the sky or distant areas. (2) Set of borders, legs, and drops used to define the limits of a performance area.