What does ēlectrus mean in Latin?

ēlectrus, a adjective, means “of amber”.

adjective

ēlectrus

ēlectrus, a, um, adj. electrum,

I. of amber: nummi, Lampr. Alex. Sev. 25, 9.

Ēlectrus, i, m.,

I. son of Perseus and father of Alcmena, Plaut. Am. prol. 99; called also Electryon, Hyg. Fab. 244.