ἄκρης

From LSJ

αἰθὴρ δ᾽ ἐλαφραῖς πτερύγων ῥιπαῖς ὑποσυρίζει (Aeschylus, Prometheus Bound 126) → The bright air fanned | whistles and shrills with rapid beat of wings.

Source

Greek (Liddell-Scott)

ἄκρης: πόλιος, «διαλελυμένως, τῆς ἀκροπόλεως», Ἡσύχ.