1. (noun)sapphire a precious transparent stone of rich blue corundum valued as a gemstone Synonyms: cerulean, sky-blue, azure, lazuline Antonyms: neutral, achromatic
2. (noun)sapphire a transparent piece of sapphire that has been cut and polished and is valued as a precious gem Synonyms: cerulean, sky-blue, azure, lazuline Antonyms: achromatic, neutral