eighteenth day of the month

a octadecagon

twenty-eight; 28

(linguistics) the theory that Old Japanese had eight vowels: /a/, /i₁/, /i₂/, /u/, /e₁/, /e₂/, /o/.

thirty-eight; 38

ostracism; a type of extra-judicial social exclusion practiced in Japan where a villager disturbing the peace of a village is shunned by the rest of them

the "Eight-Hand Mirror", one of the three sacred treasures comprising the Imperial Regalia of Japan

(Shinto) eight million, used to depict the number of kami / a myriad; a multitude; a countless large number or amount

Yanba (a koaza in Kawarahata, Naganohara, Agatsuma district, Gunma Prefecture, Japan)

(Japanese mythology, Shinto) Yamata no Orochi, a legendary dragon that was slain by Susanoo