i. An aeronautical light arranged, either through optical design or mechanical motion, to be visible to all azimuths, either continuously or consecutively, to designate a particular point on the surface of the earth. It emits a distinctive, or characteristic, signal used to determine bearings, courses, or locations and guides, orients, or warns aircraft in flight.
ii. A structure, building, or station where such a device is mounted or located.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved