Sheaf of planes
When extending the concept of line to the line at infinity, a set of parallel planes can be seen as a sheaf of planes intersecting in a line at infinity. To distinguish it from the more common definition the adjective parallel can be added to it, resulting in the expression: parallel sheaf of planes. 
- Definition on Mathworld Wolfram
- Sommerville, D. M. Y. (1909). "Classification of Geometries with Projective Metric". Proceedings of the Edinburgh Mathematical Society. 28: 25. doi: 10.1017/S0013091500034763.
- Vitutor: Sheaf of Planes