εἰκώ

From LSJ

λίγεια μινύρεται θαμίζουσα μάλιστ' ἀηδών → the sweet-voiced nightingale mourns constantly, the sweet-voiced nightingale most loves to warble

Source

Russian (Dvoretsky)

εἰκώ: Her., Aesch. acc. к εἰκών.