Combat Rounds are units of time equal to 12 seconds. The term is often used imprecisely throughout combat, as characters will often refer to "the round," "our round" and "their round" as though these are different things. Technically (noting that this is a matter of little importance in game), the combat round is composed of two parts, "ours" and "theirs," with inconsistencies that result due to members of our side and their side being stun locked and therefore losing their attack turn, or "their round." However, as the exact time passing is less important than the ebb and flow of each side attacking and giving up attacks, and as it is assumed that "our" round and "their" round is happening simultaneously, this distinction doesn't in fact need to be made. The term "combat round" should therefore be treated as a loose convention for managing the complexity of combat time periods.
Combat rounds for both sides are divided into action points (AP). Depending on the combatant, the exact length of an individual's AP is dependent on their encumbrance and strength. For a character with 3 AP, each AP would require 4 seconds, as the character would be hampered by encumbrance and probably armour. A character with 5 AP could perform the same action in 2.4 seconds.
Five rounds = 1 minute of time.