Associated with the base of an organism or structure.
Basic, elementary; relating to, or forming, the base, or point of origin.
In a phylogenetic tree, being a group, or member of a group, which diverged earlier. The earliest clade to branch in a larger clade.
Of a minimal level that is necessary for maintaining the health or life of an organism.
base, bottom, minimum
Any basal structure or part
Structural
Of or relating to construction or to architecture
Of, relating to, or caused by large-scale movements of the Earth's (or a similar planet's) lithosphere
momentous, utter, vast