1.Definition: (followed by `to') applying exclusively to a given category or condition or locality

"A species unique to Australia"

2.Definition: highly unusual or rare but not the single instance

"Spoke with a unique accent", "Had unique ability in raising funds", "A frankness unique in literature", "A unique dining experience"

3.Definition: radically distinctive and without equal

"Bach was unique in his handling of counterpoint"

Related Adjective(s):alone, unequaled, unequalled, unparalleled

4.Definition: the single one of its kind

"The unique existing example of Donne's handwriting", "A unique copy of an ancient manuscript", "Certain types of problems have unique solutions"

Related Adjective(s):singular