a physical or abstract base, starting point, or underlying support

A foundational or introductory subject that provides essential knowledge for further specialized study or a major.

elementary education

the socio-economic structure of a society, especially in Marxist theory, which determines the superstructure

basic rate (as in ISDN)

a basic issue or core question that serves as the foundation for a field of study, a theory, or a discussion

accruals basis (accounting)

cash basis (accounting)

having no prior knowledge or study in a specific area of learning

underlying medical condition

(computing) infrastructure as a service (IaaS)