# Orientable Surface

## orientable surface

[‚ȯr·ē‚en·tə·bəl ′sər·fəs] (mathematics)

A surface for which an object resting on one side of it cannot be moved continuously over it to get to the other side without going around an edge.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

The following article is from

*The Great Soviet Encyclopedia*(1979). It might be outdated or ideologically biased.## Orientable Surface

a surface that can be oriented. An orientable surface is the opposite of a nonorientable surface. On a nonorientable surface, for example, a Möbius band, there always exist closed curves such that the orientation of a small neighborhood of a point moving along the curve is reversed when the entire curve is traversed. The projective plane is an important example of a closed nonorientable surface.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.