Webster's Revised Unabridged Dictionary · 1913

Rare

Rare (râr) , adjective

[Compare Rather, Rath.]

Early. [Obsolete]
Rude mechanicals that rare and late Work in the market place. — Chapman

Rare (râr"ẽr) , adjective

[Compare Anglo-Saxon hrēr, or English rare early. r18.]

Nearly raw; partially cooked; not thoroughly cooked; underdone; as, rare beef or mutton.
New-laid eggs, which Baucis' busy care Turned by a gentle fire, and roasted rare. — Dryden

This word is in common use in the United States, but in England its synonym underdone is preferred.

Rare (râr"ẽr) , adjective

[French, from Latin rarus thin, rare.]

1.
Not frequent; seldom met with or occurring; unusual; as, a rare event.
2.
Of an uncommon nature; unusually excellent; valuable to a degree seldom found.
Rare work, all filled with terror and delight. — Cowley
Above the rest I judge one beauty rare. — Dryden
3.
Thinly scattered; dispersed.
Those rare and solitary, these in flocks. — Milton
4.
Characterized by wide separation of parts; of loose texture; not thick or dense; thin; as, a rare atmosphere at high elevations.
Water is nineteen times lighter, and by consequence nineteen times rarer, than gold. — Sir I. Newton
A perfect union of wit and judgment is one of the rarest things in the world. — Burke
When any particular piece of money grew very scarce, it was often recoined by a succeeding emperor. — Addison