adj. 1 a dealing with or arising from the simplest facts of a subject; rudimentary, introductory. b simple. 2 Chem. not decomposable. elementary particle Physics any of several subatomic particles supposedly not decomposable into simpler ones. elementary school a school in which elementary subjects are taught to young children. elementarily adv. elementariness n.
[ ME f. L elementarius (as ELEMENT) ]