constituent (adj.) Look up constituent at Dictionary.com
"essential, characteristic," 1660s, from Latin constituentem (nominative constituens), present participle of constituere (see constitute). Meaning "that appoints or elects a representative to a body" is from 1714.
constituent (n.) Look up constituent at Dictionary.com
1620s, "one who appoints or elects a representative," from Latin constituentem (nominative constituens), present participle of constituere (see constitute). The notion is "to make up or compose" a body by appointing or electing a representative.