coordinate system

an ecosystem (system of an ecological community and its environment)

inertial frame of reference

Kyūjitai form of 体系: system; organization

aggressive in relationships

(slang) denpa-kei person: one who acts strangely (disconnected from reality), often having wild fantasies and often saying strange things

A person not interested in marriage or dating; a person who is considered insufficiently assertive / A man deemed insufficiently masculine or manly

the imperial family line

a nervous system

Alternative form of ヴィジュアル系 (vijuaru-kei)