Meaning

• (usually in the plural) A leading or primary principle, rule, law, or article, which serves as the groundwork of a system; an essential part

  "one of the fundamentals of linear algebra"

• The lowest frequency of a periodic waveform.

• The lowest partial of a complex tone.

Meaning

• Pertaining to the foundation or basis; serving for the foundation.

• Essential, as an element, principle, or law; important; original; elementary.

  "A need for belonging seems fundamental to humans."