office pool - a group of people competing against each other by picking winners of sporting events; football games, basketball tournaments, soccer matches, etc.
pick em pool - The goal is to pick the most winners of a league's events. Typically, pick em is reserved for games where there are only 2 teams vying for the win; NFL, College football, soccer. The number of games per week at team plays also has a bearing on whether a league is good for pick em pools.
fantasy league/game - A game os stats accumulation. Contestants choose a roster of players in the specified league (MLB, NFL, NBA, NHL, etc.), no matter the team the play for, in hopes that those players' stats, when added together, will be more than other contestants' roster stats.
(To be good at fantasy leagues takes a lot of time to sift thru thousands of stats for all of the different players.)
push - Even money. No favorite, no underdog.
spread - The favorite must win by at least the spread points for you to win your pick. Points the odds makers take away from the favorite team to even the teams up.
favorite - The team that is expected to win.
underdog - The team given less of a chance to win.
away team - Team not playing game in their own stadium.
home team - Team playing in their own stadium, in their city.
bracket - A tournament "scaffolding" showing the teams that will play each other. Winners move to the next round. 1/2 the teams lose in each round, until 1 team is left, which is the champion.