The Collaborative International Dictionary of English v.0.48:
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.
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