intercentrum

from The Century Dictionary.

• noun In anatomy, an intermediate vertebral centrum; a centrum interpolated between two others, as in the extinct batrachian order Ganocephala. Such a centrum occupies the position, and to some extent has the relations, of the intervertebral substance of ordinary vertebræ.
• noun Same as centrum, 2 .

from the GNU version of the Collaborative International Dictionary of English.

• noun (Anat.) The median of the three elements composing the centra of the vertebræ in some fossil batrachians.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun anatomy The median of the three elements composing the centra of the vertebrae in some fossil batrachians.