a casement window in which the inner end of the sash slides along a track on the sill as the sash swings outward.

What does a projected mean?

The adjective projected describes something that is predicted or estimated, or parts of something that extend beyond the rest, like projected pillars that rise above a building's roof. ... Projected, the adjective form of project, is used to describe such a prediction.

Why do you construct projected windows in residential buildings?

The obvious benefit of this is to control wind, rain or ventilation into space to the exact degree that you like. Top-hung casement windows are probably the best solution for the weather-facing side of any building, as you can have them open without admitting any rain or severe winds.