means a temporary agreement between enemies or opponents to stop fighting or arguing for a while.

from From Middle English 'trewes,' the plural of 'trewe' meaning faith, pledge, or promise — going back to Old English 'trēow' (faith, good faith), a relative of 'true' and 'trust.' So a truce is literally a swapping of good-faith promises, the plural form sticking because a pledge meant nothing unless both sides made one.