Which type of window is hinged on one of the vertical sides?

A casement window is designed with hinges on one of its vertical sides, allowing it to swing open outward, providing excellent ventilation and an unobstructed view. This functionality is ideal for capturing breezes because it can be positioned to catch the wind effectively, while the sealing against the frame when closed contributes to energy efficiency.

In contrast, a double-hung window operates with two vertically sliding sashes, which means it does not hinge but rather slides up and down. A sliding window, similarly, has sashes that slide horizontally and does not incorporate hinges on the sides. An awning window, while also hinged, is hinged at the top and opens outward from the bottom, distinguishing itself from the vertical hinge mechanism of a casement window. This understanding emphasizes the unique characteristics of each window type and highlights why the casement window is the correct answer to the question.