Ap'pe-tençe or Ap'pe-ten-cy, n.

n. [Fr. appétence, Lat. appetentia, from appetere, to strive after, to long for, from ad and petere, to fall upon, to aim at, to seek.]

1. Fixed and strong natural desire; eager appetite; as, appetence for food, for rest, &c.; specifically, an 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.
2. The tendency of organized bodies to select and imbibe such portions of matter as serve to support and nourish them, or such particles as are designed, through their agency, to carry on the animal or vegetable economy.

These lacteals have mouths, and by animal selection or appetency they absorb such part of the fluid as is agreeable to their palate. Darwin.