τονή
From LSJ
ὁ κόσμος ἀλλοίωσις, ὁ βίος ὑπόληψις → the universe is flux, life is opinion | the universe is transformation: life is opinion | the universe is change, life is a fleeting impression | the universe—mutation: life—opinion
English (LSJ)
ἡ,
A prolongation of a note at the same pitch, Cleonid.Harm.14.
Greek (Liddell-Scott)
τονή: ἡ, ἐν τῇ μελοποιΐα, «... τονὴ δὲ ἡ ἐπὶ πλείονα χρόνον μονὴ κατὰ μίαν γενομένη προφορὰν τῆς φωνῆς» Εὐκλ. Εἰσαγ. Ἁρμον. σ. 22, 7.