Mission Statement
The terms are abbreviations that people use in each match, if you're a complete beginner and get into a match with people that have a little bit more time playing than you. You might see some of these things pop up.
Terms?
In League of Legends there are a lot on abbreviations that are called "Terms". These are things that the players use to type in game and commmunicate faster with others.
AFK
Away from keyboard. This means that the person is leaving, or doesn't have their hands on the keyboard to be able to play.
All-in
This is used when you commit all of your champions resources into one target. Usually the strongest enemy, to shut them down faster and have a better chance to win.
AoE
Area of Effect. This means a champion ability that can hit multiple champions at the same time.
OOM
Out Of Mana. This means that you're out of resources and are unable to fight.
MIA
Missing In Action. This means that the enemy left and is unseen, usually to help another lane or get a kill.
TF
Team Fight. This means when all 5 players of each team gather up together and fight eachother.