unique as in (followed by `to') applying exclusively to a given category or condition or locality
"a species unique to Australia"
unique as in the single one of its kind
"a singular example"
"the unique existing example of Donne's handwriting"
"a unique copy of an ancient manuscript"
"certain types of problems have unique solutions"
singular the form of a word that is used to denote a singleton ; unusual or striking; beyond or deviating from the usual or expected; being a single and separate person or thing; composed of one member, set, or kind ; grammatical number category referring to a single item or unit ; the single one of its kind
unique as in highly unusual or rare but not the single instance