The Concise Oxford Dictionary of World Religions (2720 page)

) that is engulfed by fire (suffering), the father (the Buddha) offers three kinds of cart (
ratha
) pulled by goats, deer, and bullocks. Wishing to have these toys, the children rush out of the house. But the father gives them all the third and best kind of cart, the one drawn by great (mah
) white bullocks. This cart is the great vehicle (mah
-y
na). (The other two are vehicles suited to people of lesser spiritual aspirations.) It is explicitly stated in this chapter that the Buddha's action is skill-in-means (
up
ya-kau
alya
). He offers three kinds of y
na but only actually gives one—the mah
-y
na or buddha-y
na or eka-y
na (‘single vehicle’)—which leads all beings to become Buddhas (
Lotus S
tra
3. 89–91).
This running together of the terms
up
ya
and y
na is crucial to understanding the meaning of y