\Ap"pe*ten*cy\, n.; pl. {Appetencies}. [L. appetentia,
fr. appetere to strive after, long for. See {Appetite}.]
1. Fixed and strong desire; esp. natural desire; a craving;
   an eager appetite.
         They had a strong appetency for reading. --Merivale.
2. Specifically: An instinctive inclination or propensity in
   animals to perform certain actions, as in the young to
   suck, in aquatic fowls to enter into water and to swim;
   the tendency of an organized body to seek what satisfies
   the wants of its organism.
         These lacteals have mouths, and by animal selection
         or appetency the absorb such part of the fluid as is
         agreeable to their palate.            --E. Darwin.
3. Natural tendency; affinity; attraction; -- used of
   inanimate objects.