heart of glass

to break, to be broken, to be destroyed, to be wrecked / to fall through; to be broken off / (informal) to go mad; to lose it

ease / simplicity / lightness, brevity

easy / simple, uncomplicated / brief, light, short

(chiefly in mathematics, physics) for simplicity; for the sake of simplicity

(colloquial) a girlfriend (a female partner in a romantic relationship)

(formal) Female third-person singular pronoun; she, her, girlfriend

(literary) they (about women or girls)

(ophthalmology) Alternative form of 硝子体

(anatomy, cardiology) Synonym of 心臓 (shinzō, “heart”) / Synonym of 心 (kokoro, “heart”) (emotions or kindness) / (card games) hearts