Noah Webster
Rarity
RAR'ITY, noun [Latin raritas.]
1. Uncommonness; infrequency.
Far from being fond of a flower for its rarity -
2. A thing valued for its scarcity.
I saw three rarities of different kinds, which pleased me more than any other shows in the place.
3. Thinness; tenuity; opposed to density; as the rarity of air.