1. A strobe light.
2. A stroboscope.
3. A spot of higher than normal intensity in the sweep of an indicator, as on a radar screen, used as a reference mark for determining distance.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.