Baron
Middle English: from Old French, from medieval Latin baro, baron- ‘man, warrior’, probably of Germanic origin.
wiktionary
From Middle English baroun, from Old French baron, Medieval Latin barō, from Frankish *barō(“servant, man, warrior”), perhaps from Proto-Germanic *barô(“carrier, bearer”), from Proto-Indo-European *bʰer-(“to bear”). Cognate with Old High German baro(“human being, man, freeman”), and perhaps to Old English beorn(“man, warrior”). Used in early Germanic law in the sense of "man, human being".
A Celtic origin has also been suggested, due to the occurrence of a Latin barones(“military official”) as early as the first century (Cornutus, On Persius' Fifth Satire). However, the OED takes this hypothetical Proto-Celtic *bar-(“hero”) to be a figment.
etymonline
baron (n.)
c. 1200, "a member of the nobility," also a low rank in the peerage, from Old French baron (nominative ber) "baron, nobleman, military leader, warrior, virtuous man, lord, husband," probably from or related to Late Latin baro "man" (source of Spanish varon, Italian barone), which is of uncertain origin. It is perhaps from Celtic or from Frankish *baro "freeman, man" or another Germanic source. In England the word merged with (probably) cognate Old English beorn "nobleman."
