TGV is a
French acronym that means "
Train à Grande Vitesse". In English this translates as "
high speed train"... interestingly enough! TGV does not stand for "Très Grande Vitesse" or other similar variations.
TGV is not a trademark, for the time being at least.
Typically, top speed of a TGV in commercial service is 300 km/h (186 mph). Under special test conditions a TGV trainset has reached 515.3 km/h (320 mph). Some speed restrictions due to the line or the train may exist, but weather (such as dense fog) does not limit speeds.
after http://www.trainweb.org/tgvpages/faq.html