unique (adj.) Look up unique at Dictionary.com
c. 1600, "single, solitary," from Middle French unique (16c.), from Latin unicus "only, single, sole, alone of its kind," from unus "one" (from PIE root *oi-no- "one, unique"). Meaning "forming the only one of its kind" is attested from 1610s; erroneous sense of "remarkable, uncommon" is attested from mid-19c. Related: Uniquely; uniqueness.