Alternative form of 孝行芋 (kōkōimo, “(Tsushima) sweet potato”)

a transverse flute / more specifically, a kind of bamboo transverse flute used to play traditional Japanese court music

hamlet, a community that is a unit of a village / burakumin area

(school slang) (being a part of) the "going-home club" (i.e. not participating in any after-school clubs)

material, physical

a historical period where social disorder is so great due to war, disease, political disorder etc. that there is little or no cultural development; Dark Ages

dark matter

暗黒時代: a historical period where social disorder is so great due to war, disease, political disorder etc. that there is little or no cultural development; Dark Ages

harmonic analysis

meeting, gathering / society, association, club