basal
adj. C1 Advanced US //ˈbeɪsəɫ// UK //bˈeɪsəl// basal
adj. at the bottom or base of something. You use it to describe the lowest part of a structure, organ, or hierarchy.
adj. situated at the bottom or base; forming the foundation or lowest part of a structure or system.
The basal cells divide rapidly to replace lost tissue.
The basal ganglia help control movement and are located deep within the brain.
In geological surveys, the basal layer of the sedimentary rock formation revealed evidence of ancient river systems that once flowed through the region.
From base + -al.