isolead curve

isolead curve

[′ī·sə‚lēd ‚kərv]
(ordnance)
A curved line, on a chart or diagram, used to show how far ahead of a moving target a weapon must be aimed to allow for the time the projectile takes to reach the target; the isolead curve connects points of equal lead on the chart or diagram.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.