Source : Webster's Revised Unabridged Dictionary (1913)

Synteresis \Syn`te*re"sis\, n. [NL., fr. Gr. ? preservation, fr.
   ? to preserve; sy`n with + ? to guard.]
   1. (Med.) Prophylaxis. [Obs.]

   2. (Metaph.) Conscience viewed as the internal repository of
      the laws of duty. --Whewell.