1)Third gear is another way of saying mackin', or pimpin'. like- 3rd gear in a mac truck.

2) Third gear is that stage when a male and female are inbetween being just friends and "officially" dating

3) It may be used to describe overdone affection between a dating couple

4) It may be used as a synonym for girlfriend or boyfriend.
1)Hey, are you in third gear with Lindsey?
2) Greg, where is your third gear?

Wow! Matt and Jamie are really third gearing it.
by Melizabeth Butler April 18, 2008
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