An elementary building block, e.g. a fundamental piece of knowledge.
A necessary commodity, a staple requirement.
Basic training.
Elementary, simple, fundamental, merely functional.
Of or pertaining to a base; having a pH greater than 7.
Unremarkable or uninteresting; boring; uncool.
Necessary, essential for life or some process.
The basis of something.
A stone laid during the construction of a (usually important) building, the laying of which is usually marked by a ceremony.