Crasis /(kr?"s?s)/

Cra·sis

Crasis

n.
  1. A mixture of constituents, as of the blood; constitution; temperament. (Med.)
  2. A contraction of two vowels (as the final and initial vowels of united words) into one long vowel, or into a diphthong; synæresis; as, cogo for coago. (Gram.)