(n.) A person or thing of a sort that there is no other such; something extraordinary; a thing that has not its equal. It is given as a name to various objects, as to a choice variety of apple, a species of medic (Medicago lupulina), a variety of pottery clay, etc.

abnormality amazement anomaly astonishing thing astonishment champion choice chosen conversation piece cream curio curiosity elect elite exception fat flower gazingstock ideal improbability jewel marvel marvelment miracle museum piece nonpareil oddity optimum paragon phenomenon phoenix pick prime prize prodigiosity prodigy queen quintessence quite a thing rarity select sensation sight something else spectacle strange thing stunner superlative the best the best ever the tops the very best wonder wonderful thing wonderment