An Etymological Dictionary of Astronomy and Astrophysics

A suspension of hostilities for a specified period of time by mutual agreement of the warring parties (Dictionary.com).

Etymology (EN): M.E. triws, trewes, originally plural of trewe “faith, treaty,” from O.E. treow “faith, truth, fidelity; promise,” cf. O.Frisian triuwe, M.Du. trouwe, Du. trouw, O.H.G. triuwa, Ger. treue “faith, faithfulness.” The Germanic word was borrowed into L.L. as tregua, hence Fr. trève.

Etymology (PE): Nâpard, literally “not war,” from negation prefix nâ-, → un-, + pard, variant of vard in prefixed nabard, âvard “fight, struggle,” ultimately from Proto-Ir. *part- “to fight, struggle,” cf. Av. pərət- “to fight, struggle.”