Rar"i*ty (?), n.; pl. Rarities (#). [L. raritas: cf. F. raret'e. See Rare.]
1.
The quality or state of being rare; rareness; thinness; as, the rarity (contrasted with the density) of gases.
2.
That which is rare; an uncommon thing; a thing valued for its scarcity.
I saw three rarities of different kinds, which pleased me more than any other shows in the place.
Addison.
© Webster 1913.