From WordNet (r) 3.0 (2006) [wn]:
headlamp
n 1: a powerful light with reflector; attached to the front of
an automobile or locomotive [syn: headlight, headlamp]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
headlamp \head"lamp`\ (h[e^]d"l[a^]mp`), n.
A powerful light with a reflector, attached to the front of
an automobile, locomotive, or other vehicle; called also
headlight.
Syn: headlight.
[WordNet 1.5]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Headlight \Head"light`\ (h[e^]d"l[imac]t`), n. (Engin.)
A light, with a powerful reflector, placed at the front of a
vehicle such as an automobile, truck, locomotive etc., to
throw light on the road or track ahead of the vehicle at
night, or in going through a dark tunnel; a headlamp.
[1913 Webster +PJC]