Source : Webster's Revised Unabridged Dictionary (1913)

In posse \In` pos"se\ [L.]
   In possibility; possible, although not yet in existence or
   come to pass; -- contradistinguished from in esse.

Posse \Pos"se\, n.
   See {Posse comitatus}.

   {In posse}. See {In posse} in the Vocabulary.