Pronunciation: (sun'blok"), [key]
1. a substance that provides a high degree of protection against sunburn, often preventing most tanning as well as burning, as by obstructing the penetration of ultraviolet rays.
2. a lotion, cream, etc., containing such a substance. Also,sun' block".
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.