Forming an exception; not ordinary; uncommon; rare.
Corresponding to something of lower dimension under a birational correspondence.
Better than the average; superior due to exception or rarity.
An exception, or something having an exceptional value
Singular; unique; special; remarkable.
Occurring once, independent of any pattern; one-time.
Something unique and remarkable.
Something that is done, created, etc. only once, and often quickly, simply, or improvisationally.