window

(noun) a framework of wood or metal that contains a glass windowpane and is built into a wall or roof to admit light or air.

(noun) a transparent opening in a vehicle that allow vision out of the sides or back; usually is capable of being opened.

(noun) a transparent panel (as of an envelope) inserted in an otherwise opaque material.

(noun) an opening that resembles a window in appearance or function. Example: "He could see them through a window in the trees."

(noun) the time period that is considered best for starting or finishing something. Examples: "The expanded window will give us time to catch the thieves." "They had a window of less than an hour when an attack would have succeeded."

(noun) a pane of glass in a window. Synonyms: windowpane. Example: "The ball shattered the window."

(noun) an opening in a wall or screen that admits light and air and through which customers can be served. Example: "He stuck his head in the window."

(noun) (computer science) a rectangular part of a computer screen that contains a display different from the rest of the screen.