what does this symbol mean?
NCS A window in a wall with its sash drawn swung open along a dashed arc

Casement window

A window hinged at the side that swings open like a door. The arc shows the way the sash opens.

This explains what a symbol represents on a drawing. Conventions vary between firms and standards, and a drawing's own legend takes precedence.

How to read it

Casement windows have side-hinged sash, usually made to swing outward, and the whole window can be opened, where a double-hung window opens only half its area (Navy, Builder 3 & 2). Because the sash swings in plan, the symbol shows the swing (TM 5-704). The Navy's Builder Basic course shows casements drawn as pairs opening out and as single sash opening in.

Also searched as: hinged window.

Look-alikes

A door symbol swings the same way; a casement sits in a window opening.

More blueprint symbols

Sources

Last reviewed September 24, 2026 by Rory Hansen. How we research

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