Shinkansen is the term used to describe Japan's high-speed bullet trains. Synonyms for this word include "bullet train" and "high-speed train." However, there are other words that can be used to describe this innovative mode of transportation. Some common synonyms for shinkansen include "fast train," "high-speed rail," and "express train." Another less commonly used term is "super-express train." Regardless of the word used to describe it, the shinkansen is a remarkable achievement of engineering and an efficient way to travel throughout Japan.