RARE, a. [L. rarus, thin.]1. Uncommon; not frequent; as a rare event; a rare phenomenon.2. Unusually excellent; valuable to a degree seldom found.Rare work, all fill'd with terror and delight.Above the rest I judge one beauty rare.3. Thinly scattered.4. Thin; porous; not dense; as a rare and attenuate substance.Water is nineteen times lighter and by consequence nineteen times rarer than gold.5. Nearly raw; imperfectly roasted or boiled; as rare beef or mutton; eggs roasted rare.