A precious stone with magical properties, supposedly found in the gizzards of cockerels; = "cock-stone". Compare gizzard stone .
Late Middle English; earliest use found in John Trevisa (c1342–?1402), translator. From classical Latin alectoria precious stone said to be found in the gizzards of cocks (Pliny) from Hellenistic Greek ἀλεκτορεία, use as noun (short for ἀλεκτορεὶα λίθος alectory stone) of feminine of ἀλεκτόρειος of a fowl from ancient Greek ἀλέκτωρ cock, lit. ‘defender’ (from the stem of ἀλέξειν to ward off + -τωρ, suffix forming agent nouns) + -ειος, suffix forming adjectives.