jacinthEnglishOxford New American Dictionaryjacinth /ˈjāsənTH, , ˈdʒeɪsənθ , ˈjasənTH, ˈdʒæsənθ / ▸ noun a reddish-orange gem variety of zircon. – ORIGIN Middle English : from Old French iacinte or medieval Latin iacintus, alteration of Latin hyacinthus (see hyacinth).