'Flag of truce' definitions:

Definition of 'flag of truce'

noun

Flag consisting of a piece of white cloth that is hoisted to signal surrender or to ask for a truce [syn: white flag, flag of truce]

From: GCIDE

Truce \Truce\, n. [OE. trewes, triwes, treowes, pl. of trewe a truce, properly, pledge of fidelity, truth, AS. tre['o]w fidelity, faith, troth. See True.]
1. (Mil.) A suspension of arms by agreement of the commanders of opposing forces; a temporary cessation of hostilities, for negotiation or other purpose; an armistice. [1913 Webster]
2. Hence, intermission of action, pain, or contest; temporary cessation; short quiet. [1913 Webster]
Where he may likeliest find Truce to his restless thoughts. --Milton. [1913 Webster]
Flag of truce (Mil.), a white flag carried or exhibited by one of the hostile parties, during the flying of which hostilities are suspended.
Truce of God, a suspension of arms promulgated by the church, which occasionally took place in the Middle Ages, putting a stop to private hostilities at or within certain periods. [1913 Webster]