TEAM ROLES

ADC (Attack Damage Carry) - bottom lane - ranged champion(marksman) - building physical DPS for most damage output through auto-attacks

Jungler - no lane - any champion, but preferably champions with the gap-closing ability or some crowd-control - farms jungle monsters and ganks other lanes

Top - usually tanks or fighters - front liners, most of the time solo lane

Mid - Typical mid player is a mage or an assassin

Sup - bottom lane - in theory, any champion, but in practice mainly champs that have useful abilities that help ADC (heal/shield, crowd-control) - in lane phase mainly stays with ADC and assist him.