1. A diagram or drawing that shows the downward projection of surficial geology along a vertical plane, for example, a portion of a stream bed drawn at right angles to the mean direction of the flow of the stream.

2. An actual exposure or cut which reveals geological features.

A diagram or drawing representing a cut at right angles to an axis.

A horizontal grid system that is laid out on the ground for determining contours, quantities of earthwork, and so on, by means of elevations of the grid points.

1. The intersection of an n-dimensional geometric figure in some euclidean space with a lower dimensional hyperplane.

2. A right inverse for the projection of a fiber bundle.

An area characteristic of a collision reaction between atomic or nuclear particles or systems, such that the number of reactions which occur equals the product of the number of target particles or systems and the number of incident particles or systems which would pass through this area if their velocities were perpendicular to it. Also known as collision cross section.