Look up parley in Wiktionary, the free dictionary.
Parley/ˈpɑrli/ is a discussion or conference, especially one between enemies over terms of a truce or other matters. For example, in Julius Caesar (a tragedy by William Shakespeare), the respective followers and armies of Brutus and Antony are ready for a truce. The root of the word parley is parler, which is the French verb "to speak"; specifically the conjugation parlez "you speak", whether as imperative or indicative. Beginning in the High Middle Ages with the expansion of monarchs, a parley, or "talk", was a meeting held between kings and their Chief Retainers. Parleys were part of the many changes in Europe, especially regarding governments. These meetings can be attributed to the formation of parliaments, which are derived from a similar root, parliamentum, simply meaning "talking".
The internationally recognized symbol for offering parley is a black flag, particularly in the context of shipping. For example, a ship at war wishing to enter parley with its attackers may raise a black flag to indicate this.
During the 18th and 19th century, it was considered one of the grossest breaches of the rules of war to attack an enemy during a parley. The British Army was accused of multiple parley violations during the American Revolutionary War, specifically arresting Continental Army officers engaged in negotiations as traitors in addition to the hanging of uniformed despatch riders as spies.