@codewizard
Trump comes from Trumpf the german word for trionfi which (apparently (wikipedia)) is the original italian word for cards that overrule cards of plain suits.
Plains are like the commoners and trionfi cards are the nobility who do not have to obey by the normal rules, or lets say, trump the normal plain suit cards, they are stronger.
Commonly you have to play the kind of cards the initial card in a turn commands. If that is for example a plain of clubs, every one has to play a club. I someone does not have a card of the kind of the initial card of the turn, than they are free to throw what ever card they want to. If they play a trionfi card, a Trumpf, they win the turn over, unless another player that also does not have the requested plain plays a higher trionfi card and wins.
Auftrumpfen in german means kinda doing a show off, to expose your capabilities.
Where do you see people playing card games sitting in circles on the ground?
(The gambling (for money) is actually a secondary thing, to improve the tension and not necessary at all)