orientable

Orientable is a mathematical term describing a surface or manifold that has two distinct sides, allowing for a consistent notion of "clockwise" or "counterclockwise" across its entire extent.

A sphere or a plane is orientable because you can distinguish inside from outside, or top from bottom, everywhere on the surface.

A Möbius strip, by contrast, is non-orientable—if you travel along it, you eventually return to your starting point flipped.

The concept matters in topology, geometry, and physics when determining whether consistent direction or handedness can be defined.