名词

1. 罕见的人（或物）；奇物;珍品
If someone or something is a rarity, they are interesting or valuable because they are so unusual.

2. 稀有;罕见
The rarity of something is the fact that it is very uncommon.

1. something unusual -- perhaps worthy of collecting

Synonym: curiocuriosityoddityoddmentpeculiarity

2. a rarified quality

e.g. the tenuity of the upper atmosphere

Synonym: tenuitylow density

3. noteworthy scarcity

Synonym: rarenessinfrequency