The Collaborative International Dictionary
To beat a parley
Parley \Par"ley\, n.; pl. Parleys. [F. parler speech, talk, fr. parler to speak, LL. parabolare, fr. L. parabola a comparison, parable, in LL., a word. See Parable, and cf. Parliament, Parlor.] Mutual discourse or conversation; discussion; hence, an oral conference with an enemy, as with regard to a truce.
We yield on parley, but are stormed in vain.
--Dryden.
To beat a parley (Mil.), to beat a drum, or sound a trumpet, as a signal for holding a conference with the enemy.
Usage examples of "to beat a parley".
At ten in the morning, a drummer in red mounted the enemys hornwork and began to beat a parley.