Can someone tell me what jet lag is?

it's nothing to worry about. It's just when you get on a plane and travel over several time zones. Here's Wikpedia's definition, they pretty much cover it. "When traveling across a number of time zones, the body clock will be out of sync with the destination time, as it experiences daylight and darkness contrary to the rhythms to which it has grown accustomed: the body's natural pattern is upset, as the rhythms that dictate times for eating, sleeping, hormone regulation and body temperature variations no longer correspond to the environment nor to each other in some cases. To the degree that the body cannot immediately realign these rhythms, it is jet lagged." You basically feel kind of tired and nauseous and may have headaches or something, that's what happened to me when I flew overnight from San Fransisco to London. To help prevent it, get lots of sleep on the flight, especially if it's overnight. Also, drink lots of water. Don't worry, you'll be fine.

It will be a tired feeling you have when you return to your own time zone. Our bodies adjust to the time zone we are in so if you go 3 hours back and then go to bed on that time zone your body will have to readjust when you return...you'll be tired and that is jet lag.

It is when you have been in the plane for along period of time and you change over alot of different time zones.Once you land you may think that it should be morning time but it turns out to be night time.It confuses your sleeping pattern then that is why you will feel so tide for a day or to until your body adjusts it self again.

I believe it's when your bladder turns into vomit twelve days after a plane trip, don't worry though, hun. It only affects people bred from sheep-dogs. Speaking of sheep-dogs, DINNA TIME!