Top Definition
The unnecessary third wheel in a group of 3 people. Tin Dogs are usually insignificant people who spend all their time in the shadow of the others.
Me? I'm their man in Havana; I'm their technical support. I'm... Oh my god... I'm the tin dog.
by Anomonon June 27, 2010
A highly useful but under-appreciated member of a group. Comes from a robotic dog ("K-9") from the "Doctor Who" TV series.
Mickey was instrumental in saving the human race, but he considered himself just a tin dog.
by peakeflix January 05, 2015

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.