1520s, "one who leads or guides," from French conductour (14c., Old French conduitor), from Latin conductor "one who hires, contractor," in Late Latin "a carrier," from conductus, past participle of conducere "to lead or bring together, contribute, serve," from assimilated form of com "with, together" (see con-) + ducere "to lead" (from PIE root *deuk- "to lead").
Earlier in same sense was conduitour (early 15c., from Old French conduitor). Meaning "a director or manager" is from 1630s; specific sense of "leader of an orchestra or chorus" is from 1784. Meaning "one who has charge of passengers and collects fares on a railroad" is 1832, American English. Physics sense of "object or device that passes heat or other energy" is from 1745; of electricity from 1737.
The office of conductor in the modern sense was not clearly distinguished from that of leader until about 1800; formerly the leader played an instrument, usually the harpsichord [Century Dictionary]
It forms all or part of: abduce; abducent; abduct; abduction; adduce; aqueduct; circumduction; conduce; conducive; conduct; conductor; conduit; deduce; deduction; dock (n.1) "ship's berth;" doge; douche; ducal; ducat; Duce; duchess; duchy; duct; ductile; duke (n.); educate; education; induce; induction; introduce; introduction; misconduct; produce; production; reduce; reduction; seduce; seduction; subduce; subduction; taut; team (n.); teem (v.1) "abound, swarm, be prolific;" tie (n.); tow (v.); traduce; transducer; tug; zugzwang.
It is the hypothetical source of/evidence for its existence is provided by: Latin dux (genitive ducis) "leader, commander," in Late Latin "governor of a province," ducere "to lead;" Old English togian "to pull, drag," teonteon "to pull, drag;" German Zaum "bridle," ziehen "to draw, pull, drag;" Middle Welsh dygaf "I draw."
English agent noun ending, corresponding to Latin -or. In native words it represents Old English -ere (Old Northumbrian also -are) "man who has to do with," from Proto-Germanic *-ari (cognates: German -er, Swedish -are, Danish -ere), from Proto-Germanic *-arjoz. Some believe this root is identical with, and perhaps a borrowing of, Latin -arius (see -ary).
Generally used with native Germanic words. In words of Latin origin, verbs derived from past participle stems of Latin ones (including most verbs in -ate) usually take the Latin ending -or, as do Latin verbs that passed through French (such as governor); but there are many exceptions (eraser, laborer, promoter, deserter; sailor, bachelor), some of which were conformed from Latin to English in late Middle English.
The use of -or and -ee in legal language (such as lessor/lessee) to distinguish actors and recipients of action has given the -or ending a tinge of professionalism, and this makes it useful in doubling words that have a professional and a non-professional sense (such as advisor/adviser, conductor/conducter, incubator/incubater, elevator/elevater).
a slang or colloquial shortening of various nouns beginning in con-, such as, from the 19th century, confidant, conundrum, conformist, convict, contract, and from the 20th century, conductor, conservative.
"guide or conductor of spirits or souls to the other world," 1835, from Greek psykhopompos "spirit-guide," a term applied to Charon, Hermes Trismegistos, Apollo, etc.; from psykhē "the soul, mind, spirit" (see psyche) + pompos "guide, conductor, escort, messenger," from pempein "to send, dispatch, guide, accompany," which is of unknown origin. "The verb has no IE etymology, nor does it show characteristics of loanwords or Pre-Greek vocabulary" [Beekes].