adjective
Relating to the basic, essential or fundamental part of something.
Very simple.
Relating to an elementary school.
(sciences) Fundamental: serving as a building block for more complicated structures or processes.
(mathematics, of an argument or proof) Straightforward, employing only basic techniques; not requiring substantial knowledge (of some particular domain, object, etc.).
(archaic) Sublunary; not celestial; belonging to the sublunary sphere, to which the four classical elements (earth, air, fire and water) were confined; composed of or pertaining to these four elements.
noun
(countable and uncountable, informal) Ellipsis of elementary school.
(countable, mythology, mysticism) A supernatural being associated with the elements.