marginally outer trapped surface
marginally outer trapped surface
[¦mär·jen·əl·ē ¦au̇d·ər ¦trapt ′sər·fəs] (relativity)
A spacelike, two-dimensional surface in a space-time such that outgoing null rays perpendicular to the surface are neither diverging nor converging.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.