Where does “Mahayana” come from?

Mahayana derives from Sanskrit महायान, composed of Sanskrit महा "great" (from Sanskrit महत् and Proto-Indo-Aryan maźʰā́) and an element from Proto-Indo-European méǵh₂s and yeh₂-.

Ancestry of “Mahayana”, step by step

Step	Language	Word	Meaning
1	Sanskrit	महायान	—
2	Sanskrit	यान	carriage, vehicle, mode of transport; moving,...
3	Proto-Indo-Aryan	yáHnam	—
4	Proto-Indo-Iranian	yáHnam	—
5	Proto-Indo-European	yéh₂-nom	—
6	Proto-Indo-European	yeh₂-	to go; to go in, enter; to ride, to travel

Every word from Proto-Indo-European yeh₂- →

Mahayana — Etymology, Origin & Word History | Etymology Explorer