An Etymological Dictionary of Astronomy and Astrophysics

1. Ease in moving, acting, or doing.
   

   2. Something that facilitates an action or process.
      

   3. A building, room, array of equipment, or a number of such things, designed to serve a particular function (TheFreeDictionary.com).

Etymology (EN): → facile; → -ity.

Etymology (PE): Âsânâk, from âsân “easy,” + relation suffix -âk, as in xorâk, pušâk, dârâk.