What is the Japanese word for master?
depends on what usage
master as in instructor sensei
there is no Japanese word for grandmaster cuz im a Grandmaster in taekwon-do i also check no word ___ Taekwondo is Korean, not Japanese, so how would that qualify you...? Anyway, 達人 (tatsujin) means 'master' or 'expert' in Japanese. In terms of a martial art, 師範 (Shihan) would mean 'master' and is an honorific that is a high enough level that it can be used interchangeably with 'grandmaster'.
Hachiko is the name of a famous dog in Japan known for his loyalty towards his master. His master passed away when theis dog was 3 yrs old and for the next 9 nine years Hachi continued to wait for his master at the train station as he did when his master was alive. 'Hachi' means the number 8 in Nihongo, the Japanese language..