rare

Etymology 1

From Middle English rare, from Old French rare, rere (“rare, uncommon”), from Latin rārus (“loose, spaced apart, thin, infrequent”), from Proto-Indo-European *h₁reh₁- (“friable, thin”). Replaced native Middle English gesen (“rare, scarce”) (from Old English gǣsne), Middle English seld (“rare, uncommon”) (from Old English selden), and Middle English seldscene (“rare, rarely seen, infrequent”) (from Old English seldsēne).

adj

1. Very uncommon; scarce.
   Black pearls are very rare and therefore very valuable.
   Plant breeding is always a numbers game.[…]The wild species we use are rich in genetic variation, and individual plants are highly heterozygous and do not breed true. In addition, we are looking for rare alleles, so the more plants we try, the better. 2013 May-June, David Van Tassel, Lee DeHaan, “Wild Plants to the Rescue”, in American Scientist, volume 101, number 3
   While many material components in Andromeda are familiar, we have also discovered rarer and more valuable materials; attributable to exposure to the Scourge, or mysterious alien technology. 2017, BioWare, Mass Effect: Andromeda (Science Fiction), Redwood City: Electronic Arts, →OCLC, PC, scene: Technology: Augmentations Codex entry
2. (of a gas) Thin; of low density.
3. (UK, slang) Good; enjoyable.
   Sees her reflection in a butcher shop. She finds it all quite rare That her meat's all vanity fair. 1981, Chris Difford (lyrics), Glenn Tilbrook (vocal), "Vanity Fair" (song)

noun

1. (gaming) A scarce or uncommon item.
   Most of the time, you do this by trading low-valued rares for more valuable ones or trading uncommons for rares. Other times it's trading cards that are in print for ones that are out of print, or low-value rares for good uncommons. 1995, George Baxter, Larry W. Smith, Mastering Magic Cards, page 116

Etymology 2

From a dialectal variant of rear, from Middle English rere, from Old English hrēr, hrēre (“not thoroughly cooked, underdone, lightly boiled”), from hrēran (“to move, shake, agitate”), from Proto-Germanic *hrōzijaną (“to stir”), from Proto-Indo-European *ḱroHs- (“to mix, stir, cook”). Related to Old English hrōr (“stirring, busy, active, strong, brave”). More at rear.

adj

1. (cooking) Particularly of meat, especially beefsteak: cooked very lightly, so the meat is still red.

Etymology 3

Variant of rear.

verb

1. (US, intransitive) To rear, rise up, start backwards.
   Frank pretended to rare back as if bedazzled, shielding his eyes with a forearm. 2006, Thomas Pynchon, Against the Day, Vintage, published 2007, page 328
2. (US, transitive) To rear, bring up, raise.
   Here I have to say that I was walking along dark-hearted, my nose out of joint about Audie's notice of her, for just as quickly as my feelings kindled, my old envy rared. 2013, Janet Peery, What the Thunder Said: A Novella and Stories

Etymology 4

Compare rather, rath.

adj

1. (obsolete) Early.