Dictionary of gambling terms used in casino's with the meanings of the words explained:
"U"
Under & Over: A choice of two side bet offered by some casinos that allows punters to bet before the deal on blackjack as to whether their two dealt cards will total under or over 13, if a player chooses correctly they win at a rate of even money or lose if incorrect and if their two cards total 13.
Upcard : The card that is drawn by the dealer in blackjack that is facing upwards and used as part of the blackjack dealers total.
Casino articles of interest:
History of online poker
Basic Rules of Poker
Poker tips and Strategys
Blackjack basic strategy
Blackjack card counting