ἔκπεσις

From LSJ

γνοίης ὅσσον ὄνων κρέσσονες ἡμίονοι → you know how much better are donkeys from mules

Source

Spanish (DGE)

-εως, ἡ
caída περὶ ἐκπέσεως ἀστέρων Cat.Cod.Astr.8(3).172.20, 175.3.