a customer of prostitutes; habitue of a red-light district

(geometry) acute angle

a self-appointed ruler / (historical, Edo period) a so-called “chivalrous man”, a gangster or gambler who stood against the samurai

open a store for business, open the curtains of an event, etc. / open a building for the first time

opening of an event or public space / opening of a new building or facility

hidden, shield, shelter

authority / power / right / privilege

核融合炉: fusion reactor

核保有国: nuclear power

臨界前核実験: subcritical nuclear experiment