серповидное украшение

From LSJ

ἐπέμψατε ἀγγέλους τοῖς ἀλλήλοις ὥστε ἔγνωτε τὸν κίνδυνον → you sent messengers to one another so that you knew the danger

Source

Russian > Greek

σίγμα, σῖγμα