Blackjack is one of the few casino games where players can make decisions that give the house less of an advantage. All casino games give some advantage to the house but, in Blackjack, the advantage to the house can be reduced to less than one percent.
Blackjack is often called 21. The game originated in France around 1700. The French name for it was vingt et un which means twenty-one. The name Blackjack came about because the dealers would call out "Blackjack" if a player was dealt an ace and a black jack, that is, a jack of spades or a jack of clubs.
The early casinos paid 10-1 for a "Blackjack". Dealers still call out "Blackjack" but the casinos no longer pay 10-1. Casinos now generally pay 3-2 for any two dealt cards that add up to 21.