to drive a vehicle or other conveyance so as to strike the back end of (another vehicle): My car was rear-ended by another driver on the highway.
2.
(of a moving vehicle or other conveyance) to strike the back end of (another vehicle or object): A freight train rear-ended the commuter train this morning.
n. the tail end; the buttocks. (Euphemistic.) : The dog bit her in the rear end.
Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. Copyright 2007. Published by McGraw Hill.
Cite This Source
Idioms & Phrases
rear end
The back part of anything, especially a vehicle, as in There's a large dent in the rear end of the car.
The buttocks, as in I'm afraid these pants don't fit my rear end. The noun rear alone has been used in both these senses, the first since the late 1700s and the second since the mid-1900s. The addition of end occurred in the first half of the 1900s.
[reer-end] 
