Rar″i‐ty (răr″ĭ‐ty̆; 277), n.; pl.Rarities (–tĭz). [L. raritas: cf. F. rareté. 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.