taillight

• tail-light; tail light

tail +‎ light

taillight (plural taillights)

1. One of a pair of red lights mounted on the rear of a vehicle, so it can be seen from the rear at night.
   • 1938, Norman Lindsay, Age of Consent, 1st Australian edition, Sydney, N.S.W.: Ure Smith, published 1962, →OCLC, page 162:

     All moved to the front street, where Grierson snibbed on his tail-light and turned to ask the trooper, "They've got the main road ploughed up farther on, haven't they?"

• rear light
• taillamp