1 - (usually in the plural) A leading or primary principle, rule, law, or article, which serves as the groundwork of a system; an essential part
2 - The lowest frequency of a periodic waveform.
3 - The lowest partial of a complex tone.
1 - Pertaining to the foundation or basis; serving for the foundation.
2 - Essential, as an element, principle, or law; important; original; elementary.





