sunblock

or sun block

[suhn-blok]

noun

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.
a lotion, cream, etc., containing such a substance.

Origin of sunblock

First recorded in 1975–80; sun + block
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

sun block in Medicine

sun block

[sŭn]

n.

A preparation, as of PABA, that prevents sunburn by filtering out the sun's ultraviolet rays, usually offering more protection than a sunscreen.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.