exceptional

Forming an exception; not ordinary; uncommon; rare.

"What an exceptional meal!"

Requiring special schooling for reasons of intellectual giftedness or physical or mental disability.

"The origins of the conditions and disorders that exceptional learners have are not always well understood."

Better than the average; superior due to exception or rarity.

"The quality of the beer was exceptional."

Corresponding to something of lower dimension under a birational correspondence.

"an exceptional curve; an exceptional divisor"

An exception, or something having an exceptional value