Trick
A trick is also sometimes referred as a "book" and constitutes a set of 4 cards. Each player contributes one of their cards to a trick.
Round
Every player begins a round with 13 cards. This means that each round consists of 13 individual tricks. The round ends once every player has discarded their cards.
Bid
A bid is the amount of tricks a team estimates that it will win during the round. Both players make individual bids which are combined to form the team bid.
Nil
A nil bid is a high risk, high reward mechanic and is essentially a bid of zero. A player who places a nil bid must not win any tricks.
Bags
A bag, also known as a sandbag, is obtained for each trick won that exceeds the bid placed by a team. For example, if a team places a bid of 3 and wins 5 tricks, they will obtain 2 bags.
Spades Broken
"Spades Broken" is a game state that occurs whenever a player runs out of a particular suit and plays the first spades card of the round. Once this state is triggered, anyone can lead with spades cards.
Lead
A lead is the first player to discard a card at the start of a trick. The lead chooses which suit other players have to follow. On the first trick of a round the lead is chosen at random. On subsequent tricks the winner of the previous trick is chosen to be the lead.
Mercy Rule
The "Mercy Rule" is an optional rule that ends the game prematurely should a team reach a negative score of -200. This is useful to prevent games that are going poorly for a team to drag on for too long.