Elementary

Webster's Dictionary of the English Language

·adj Pertaining to one of the four elements, air, water, earth, fire.

II. Elementary ·adj Having only one principle or constituent part; consisting of a single element; simple; uncompounded; as, an elementary substance.

III. Elementary ·adj Pertaining to, or treating of, the elements, rudiments, or first principles of anything; initial; rudimental; introductory; as, an elementary treatise.