A turn is considered to take 10 in-game time minutes in the characters’ living world (not actual time, but time in the game).
One turn equals 10 minutes, except in combat where 10 rounds (at 6 seconds apiece) would equal one turn.
Characters also need to take a break once in awhile. When adventuring, characters need to rest one turn every hour – in other words, a 10 minute break once an hour for a party dashing about fighting and dragging loot. If the party is actually running for one hour (triple the normal speed), the characters would need to rest at least 2 turns (20 minutes).
Ready for more?