PTEr 21.b:60[2] :ר׳ אחא אמ׳ לה מן אולפן ר׳ יוסי אמר לה מן דיעה‏ : PN(1) said to him, it was from "learning," PN(2) said to him, it was from "opinion."
See the entire entry for ˀulpān, ˀulpānā n.m. learning, instruction