Lancet Windows - Tall narrow Gothic windows with sharply pointed arched tops.

Lap Siding - See clapboard. Also called weatherboard.

Leaded Glass Window - A window having small panes of various decorative shapes held in place by pieces of lead; glass may be clear, etched, stained or beveled.

Lintel - A horizontal beam over a door or window which carries the weight of the wall above; usually made of stone or wood.