before 1050;Middle Englishfelowe, felawe,late Old Englishfēolaga < Old Norsefēlagi partner in a joint undertaking, equivalent to fē money, property (cognate with Old Englishfeoh,GermanVieh) + -lagi bedfellow, comrade; akin to lair1, lie2
O.E. feolaga "partner," from O.N. felagi, from fe "money" + verbal base denoting "lay." Sense is of "one who puts down money with another in a joint venture." Used familiarly since M.E. for "man, male person," but not etymologically masculine. University senses (c.1449, corresponding to L. socius) evolved from notion of "one of the corporation who constitute a college" and who are paid from its revenues. Fellow-feeling (1613) attempted to translate L. compassio and Gk. sympatheia. First record of fellow-traveler in sense of "one who sympathizes with the Communist movement but is not a party member," is from 1936, translating Rus. poputchik.