intermedium

 
Pronunciation: /ˌɪntəˈmiːdɪəm/

noun (plural intermedia /-ˈmiːdɪə/)

Zoology
  • (in tetrapods) a carpal in the centre of the wrist joint, or a tarsal in the centre of the ankle joint.

Origin:

late 16th century (denoting an intervening action or performance): from late Latin, neuter (used as a noun) of Latin intermedius 'intermediate'