i would have thought the other questions in this catagory may have given it away... you would probably know them as commercials
(why is it i know what a fawcet, a "fanny" & a daiper is??)
An advert is something that advertises a product. It can be advertised on the radio, television, or simply from word of mouth. It is advertised so that people will hear about it and hopefully want to buy it.