What is "basi-"

Basi- \Ba"si-\ A combining form, especially in anatomical and botanical words, to indicate the base or position at or near a base; forming a base; as, basibranchials, the most ventral of the cartilages or bones of the branchial arches; basicranial, situated at the base of the cranium; basifacial, basitemporal, etc.

pre. (context anatomy botany English) Positioned at the base; forming a base.