Definition of "headlamp"

The automobile headlamp uses either a parabolic reflector or a slight modification of it to obtain a concentrated light beam.

1940, Ralph A. Richardson, Optics and Wheels, General Motors Corporation, p. 13

With its long tapered cowcatcher, massive headlamp and enormous diamond smokestack behind, wagon-top boiler, high running-plate above the driving-wheels reached from a front door in the square side-window cab, cylinders with slide valves mounted on top, and double bogie tender, General in its present form is typical of much earlier American locomotive practice.

1942 February, “Notes and News: An Historic American Locomotive”, in Railway Magazine, page 56