I come from a card-playing family. My parents preferred canasta and pinochle, and I recall many happy nights at our mountain cabin, shuffling and dealing.Once we were stranded almost 24 hours on a train blocked by an avalanche; we passed the time playing cards. In high school, some classmates taught me bridge -- a game where play counted more than luck; you could win even with low cards. Once I learned bridge, I never went back to the other games. [And I'm not skilled enough at deception to play poker.]
In bridge the players bid for a contract -- the number of tricks they'll take -- either in a suit or "no trump." Cards in the trump suit beat higher cards in other suits. In no trump contracts, the highest card of the suit led wins the trick.
That's how I think of "trump" -- a kind of wild card. As a verb, it means to prevail over even the best of others. There are other phrases, of course, like "trump up," which means to exaggerate or deceive.
I expect the headline writers to pun a lot on the word in the next few years. I'd settle for a new deal.