rare

a. [ Compar. Rarer superl. Rarest. ] [ Cf. AS. hrēr, or E. rare early. √18. ] Nearly raw; partially cooked; not thoroughly cooked; underdone; as, rare beef or mutton. [ 1913 Webster ]

New-laid eggs, which Baucis' busy care
Turned by a gentle fire, and roasted rare. Dryden. [ 1913 Webster ]

☞ This word is in common use in the United States, but in England its synonym underdone is preferred. [ 1913 Webster ]

a. [ Compar. Rarer superl. Rarest. ] [ F., fr. L. rarus thin, rare. ] 1. Not frequent; seldom met with or occurring; unusual; as, a rare event. [ 1913 Webster ]

2. Of an uncommon nature; unusually excellent; valuable to a degree seldom found. [ 1913 Webster ]

Rare work, all filled with terror and delight. Cowley. [ 1913 Webster ]

Above the rest I judge one beauty rare. Dryden. [ 1913 Webster ]

3. Thinly scattered; dispersed. [ 1913 Webster ]

Those rare and solitary, these in flocks. Milton. [ 1913 Webster ]

4. Characterized by wide separation of parts; of loose texture; not thick or dense; thin; as, a rare atmosphere at high elevations. [ 1913 Webster ]

Water is nineteen times lighter, and by consequence nineteen times rarer, than gold. Sir I. Newton. [ 1913 Webster ]

Syn. -- Scarce; infrequent; unusual; uncommon; singular; extraordinary; incomparable. -- Rare, Scarce. We call a thing rare when but few examples, specimens, or instances of it are ever to be met with; as, a rare plant. We speak of a thing as scarce, which, though usually abundant, is for the time being to be had only in diminished quantities; as, a bad harvest makes corn scarce. [ 1913 Webster ]

A perfect union of wit and judgment is one of the rarest things in the world. Burke. [ 1913 Webster ]

When any particular piece of money grew very scarce, it was often recoined by a succeeding emperor. Addison. [ 1913 Webster ]

n. A dainty morsel; a Welsh rabbit. See Welsh rabbit, under Rabbit. [ 1913 Webster ]

n. [ Contr. fr. rarity-show. ] A show carried about in a box; a peep show. Pope. [ 1913 Webster ]

n. [ Cf. F. raréfaction. See Rarefy. ] The act or process of rarefying; the state of being rarefied; -- opposed to condensation; as, the rarefaction of air. [ 1913 Webster ]

a. [ Cf. F. raréfiable. ] Capable of being rarefied. Boyle. [ 1913 Webster ]

v. t. [ imp. & p. p. Rarefied p. pr. & vb. n. Rarefying ] [ F. raréfier; L. rarus rare + -ficare (in comp.) to make; cf. L. rarefacere. See -fy. ] To make rare, thin, porous, or less dense; to expand or enlarge without adding any new portion of matter to; -- opposed to condense. [ 1913 Webster ]

v. i. To become less dense; to become thin and porous. “Earth rarefies to dew.” Dryden. [ 1913 Webster ]