According to Wikipedia a baguette (pronounced /bæˈɡɛt/) is a specific shape of bread, commonly made from basic lean dough, a simple guideline set down by French law, distinguishable by its exaggerated length, crisp crust, and slashes cut into it to enable proper expansion of gases and thus formation of the crumb, the inner soft part of bread.
The standard diameter of a baguette is approximately 5 or 6 cm, but the bread itself can be up to a meter in length, though usually about 60 cm.
A Parisian baguette typically weighs 250 grams (8.8 oz for us heathens), but this is not legally regulated and varies by region.
There it is.
I have also read that the number of slashes must be odd, and that the French regarded loaves with an even number to be inferior. Over here it would be simply regarded as bringing bad luck!