Which window type consists of narrow overlapping glass sections that swing outward?

The window type that consists of narrow overlapping glass sections that swing outward is known as a jalousie window. Jalousie windows are characterized by their unique blade design, which allows the user to control the amount of airflow and light entering a space. Each glass slat can be opened or closed individually, providing flexibility in ventilation, while the overlapping design helps to minimize water intrusion during light rain.

In contrast, the other window types mentioned do not share this specific construction or functionality. Plane windows are flat, without any movable parts. Horizontal sliding windows operate on a track and slide horizontally, while casement windows are hinged on one side and swing outward but do not have the overlapping glass sections characteristic of jalousies.