Sliding windows have sashes which slide side-to-side and are considered all-purpose window. Sliders have pleasant sight-lines and can be an economical option in designs where the casement look is required.

Suitable places to fix them.
Sliding windows are most commonly found in places with an unobstructed view or where maximum ventilation is required. These windows are often placed in places which can be harder to reach (eg. behind a kitchen sink or above a soaking tub).