We do not currently know of any synonyms for Mahayana.
The proper noun Mahayana is defined as:
A school of Buddhism widely practised in China, Japan, Korea and Mongolia and accepting non-Pali canon scriptures, that holds belief in gods in contrast to Theravada which does not, that teaches that all can achieve salvation, and has more emphasis on social concerns and is more liberal, in general, than Theravada.
