constituent

an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a system

“a component or constituent element of a system”

an abstract part of something

“two constituents of a musical composition are melody and harmony”

something determined in relation to something that includes it

“the animal constituent of plankton”

constitutional in the structure of something (especially your physical makeup)

a word or phrase or clause forming part of a larger grammatical construction

a member of a constituency; a citizen who is represented in a government by officials for whom he or she votes

“needs continued support by constituents to be re-elected”