The terms Hinayana (Theg-dman) and Mahayana (Theg-chen), meaning modest or
“lesser” vehicle and vast or “greater” vehicle, first appeared in The Sutras on Far-reaching
Discriminating Awareness (Sher-phyin-gyi mdo, Skt. Prajnaparamita Sutras; The Perfection of
Wisdom Sutras), as a way of expressing the superiority of Mahayana. Historically, there were
eighteen schools that predated Mahayana, each with its own slightly different version of the
monastic rules of discipline (‘ dul-ba, Skt. vinaya).