1670s, "a nun," from clergy + woman on the model of clergyman. Not seriously as "woman pastor, woman of the clerical profession" until 1871; in between it was used humorously for "old woman" or "domineering wife of a clergyman." Clergess as "member of a female religious order" is attested from late 14c.; clergy-feme as "clergyman's wife or woman" is attested from 1580s.
"clergyman," c. 1500, from reverend (adj.). Used as a courteous or respectful address from late 15c.
mid-14c., "minister of a chapel," from Old French chapelein "clergyman" (Modern French chapelain), from Medieval Latin cappellanus "clergyman," literally "custodian of (St. Martin's) cloak;" see chapel.
It replaced late Old English capellane (from the same Medieval Latin source), the sense of which was "clergyman who conducts private religious services," originally in great households; this sense continued in chaplain and later was extended to clergymen in military regiments, prisons, etc.
"clergyman living according to rules," c. 1200 (late 12c. as a surname), from Anglo-French canun, from Old North French canonie (Modern French chanoine), from Church Latin canonicus "clergyman living under a rule," noun use of Latin adjective canonicus "according to rule" (in ecclesiastical use, "pertaining to the rules or institutes of the church canonical"), from Greek kanonikos, from kanon "rule" (see canon (n.1)).
"one who celebrates" in any sense, 1731, from French célébrant "officiating clergyman" (in celebrating the eucharist) or directly from Latin celebrantem (nominative celebrans), present participle of celebrare "assemble together; sing the praises of; practice often" (see celebrate).
also metre, "fundamental unit of length of the metric system," originally intended to be one ten-millionth of the length of a quadrant of the meridian, 1797, from French mètre (18c.), from Greek metron "measure," from PIE root *me- (2) "to measure." Developed by French Academy of Sciences for system of weights and measures based on a decimal system originated 1670 by French clergyman Gabriel Mouton.