syndesmosis
Concise Oxford English Dictionary © 2008 Oxford University Press:
syndesmosis /ˌsɪndɛzˈməʊsɪs/
▶noun (pl. syndesmoses /-siːz/) Anatomy an immovable joint in which bones are joined by connective tissue (e.g. between the fibula and tibia at the ankle).
– origin C16: mod. L., from Gk sundesmos ‘binding, fastening’.
'syndesmosis' also found in these Oxford entries:

