/ray"dahr/ , n.
1. Electronics. a device for determining the presence and location of an object by measuring the time for the echo of a radio wave to return from it and the direction from which it returns.
2. a means or sense of awareness or perception: lobbyists working under the media's radar.
[ 1940-45, Amer.; ra ( dio ) d ( etecting ) a ( nd ) r ( anging ) ]