synosteosis

from The Collaborative International Dictionary of English v.0.48

Synosteosis \Syn*os`te*o"sis\, n.; pl. {Synosteoses}. [NL., fr.
   Gr. sy`n with + ? bone.] (Anat.)
   Union by means of bone; the complete closing up and
   obliteration of sutures.
   [1913 Webster]