A piece of
1960s slang. "Boss" meant "most
excellent", perhaps. Some boss sounds from the new 45 by
Jefferson Airplane, man, right after this message from
Pepsi; "boss" was one of those words that got
assimilated into the
mainstream a little too quickly.
Ford's revamped circa-1968 Mustang, bigger and beefier than the original, had the nickname "Boss Hoss". It was boss, though you might cringe at the man using such a word; on the other hand, if you were into cars, you probably weren't all too concerned that some Madison Avenue adman had appropriated one of your favorite superlatives.
Verve Records, after having signed a bunch of Boston bands, and with no idea as to what to do with them, dubbed the various musics they made "The Bosstown Sound". Not so boss.