Corresponding to something of lower dimension under a birational correspondence.
Forming an exception; not ordinary; uncommon; rare.
Better than the average; superior due to exception or rarity.
An exception, or something having an exceptional value
able to "pass", or be accepted as a member of a race, sex or other group to which society would not otherwise regard one as belonging.
That may be passed or traversed.
Tolerable; adequate; no more than satisfactory.