What is the direction of flow of electrons? What is meant by conventionally in the ncert reader?

Dear Student, The direction of electric current is by convention the direction in which a positive charge would move. Thus, the current in the external circuit is directed away from the positive terminal and toward the negative terminal of the battery. Electrons would actually move through the wires in the opposite direction.   So,Current flows from positive to negative terminals of the battery and is opposite to the flow of electrons which flow from negative to positive. Regards