c.1400, "to enter into negotiations," especially "discuss or arrange peace terms;" also "to treat (someone) in a certain way," from Anglo-French entretier, Old French entraiter "to treat," from en- "make" (see en-(1)) + traiter "to treat" (see treat, v.). Meaning "to beseech, implore, plead with (someone)" is from early 15c.; meaning "to plead for (someone)" is from mid-15c. Related: Entreated; entreating.