Different door styles fit different applications in your home. A French door is a door with multiple glass panes extending for most or all of its length. They are often installed as a pair - or in multiple pairs - where one of the pair may be fixed indefinitely with locks or posts.They are most frequently used at the back of a home leading to a deck, garden or patio, but may also be used as a single interior door. Glossary > A Garden door is usually installed in a pair or in a group of three panels. One panel operates as a regular door while the other panel opens window-style and comes complete with screen. On three-wide Garden door units the third panel remains fixed. A Patio door is sliding door made of two large panes of glass set in sashes, with one pane stationary and one operable. The glass in a patio door may extend from top to bottom, or the bottom of the door may include a decorative panel. Patio doors are available in a wide range of widths.