Chamberlain
Middle English (denoting a servant in a bedchamber): via Old French from Old Saxon kamera, from Latin camera ‘vault’ (see chamber).
wiktionary
From Middle English chamberlein, chaumberlein, chaumberleyn, from Anglo-Norman chamberlenc, Old French chamberlayn, chamberlenc(“chamberlain”), from Frankish *kamarling(“chamberlain”), equivalent to *kamer(“chamber”) + *-ling(“-ling”). Cognate with Old High German chamarling(“chamberlain”). More at chamber, -ling.
etymonline
chamberlain (n.)
mid-13c., etymologically "person who manages a chamber or chambers," but by the time the word reached English it had evolved to describe an important royal officer of various duties, such as "one who attends a king or person of high rank in his or her private chamber," and especially "keeper of the treasure-chamber;" from Old French chamberlenc "chamberlain, steward, treasurer" (Modern French chambellan), from a Germanic source (perhaps Frankish *kamerling; compare Old High German chamarling, German Kämmerling), from Latin camera "chamber, room" (see camera) + Germanic diminutive suffix -ling. As "chief financial officer of the king's household" from mid-15c.
