Webster’s Revised Unabridged Dictionary · 1913
Eucairite
Eu·cai′rite, n. [Gr. εὔκαιρος seasonable, opportune; εὖ well, good + καιρός season.] (Min.) A metallic mineral, a selenide of copper and silver; — so called by Berzelius on account of its being found soon after the discovery of the metal selenium.