How big is a semi truck?

The correct use of the Word Semi is to refer to the trailer, if a trailer has wheels in the front and back it is a 'full' trailer. A trailer pulled by a tractor/truck using a fifth wheel connection on the front and only having wheels in the back is referred to as a 'semi' trailer. The tractor trailer combination weights approx. 34,000 lbs empty, 80,000 lbs loaded. The tractor itself is around 18,000 lbs. Trailers vary from approx. 30-53 feet with the tractor adding around 12 feet for a total of around 65 feet. The standard height is 13' 6" tall.