1640s, "constituent part or element" (earlier "one of a group of persons," 1560s), from Latin componentem (nominative componens), present participle of componere "to put together, to collect a whole from several parts," from com "with, together" (see com-) + ponere "to place" (see position (n.)). Related: Componential.
Meaning "mechanical part of a bicycle, automobile, etc." is from 1896. As an adjective, "constituent, entering into the composition of," from 1660s.