The oldest document from Neishabur is Avesta, which refers to the word “Reyunt” meaning great and glory. This word was probably the word Rivend, now the name of the village is around Neishabur. In some texts of the Islamic historic books, the other name of Neishabur is “ABAR SHAHR” , which means great city. On some old coins that discovered in Neyshabur has written “ABAR SHAHR”.Also there is on those coins, the portrait of “Ghobad”, one of Sassanid kings.
there is some documents in Afghanistan that in very time ago, Afghanistan had a king named “NIKEFOOR” who His dominance was extended to Neyshabur, and according of that old historic texts, Nikefoor made this city and named it “Nisefoor”. this name in over time chenged to “Nisafoor” and then “Neyahbur”.
In Sassanid dynasty, the word “Neyshabur”, in anywhere has written “NEEWSHAPOOR”, that means “Shapoor good work”! In most of historic books, has written that the first Shapoor -one of Sassanid dynasty kings- made Neyshabur and the second Shapoor rebuild it after a huge earthquake.
Again Neyshabur was known as “ABARSHAR” in the early days of Islam. In the coins of the “Umayyad” and “Abbasid” dynasty, this name is mentioned.
Of course one of Neyshabur’s nicknames is “OM-AL-BLAD” that means mother of citys. because in that time Neyshabur was one of four big city of Islam land.