ἰσορρόπησις
From LSJ
τίς δ' οἶδεν εἰ τὸ ζῆν μέν ἐστι κατθανεῖν, τὸ κατθανεῖν δὲ ζῆν κάτω νομίζεται → who knows if life is death, and if in the underworld death is considered life
English (LSJ)
εως, ἡ, equipoise, equilibrium, Hero Spir.1.1.
Greek (Liddell-Scott)
ἰσορρόπησις: -εως, ἡ, = τῷ ἑπομ., Ἥρων ἐν Ἀρχ. Μαθηματ. σελ. 153.