The Collaborative International Dictionary of English v.0.48:

Boss \Boss\ (b[o^]s), v. t. [imp. & p. p. Bossed (b[o^]st); p.
   pr. & vb. n. Bossing.] [OE. bocen, fr. OF. bocier. See the
   preceding word.]
   To ornament with bosses; to stud.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Boss \Boss\, n. [D. baas master.]
   A master workman or superintendent; a director or manager; a
   political dictator. [Slang, U. S.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Boss \Boss\ (b[o^]s; 115), n.; pl. Bosses (-[e^]z). [OE. boce,
   bose, boche, OF. boce, boche, bosse, F. bosse, of G. origin;
   cf. OHG. b[=o]zo tuft, bunch, OHG. b[=o]zan, MHG. b[^o]zen,
   to beat. See Beat, and cf. Botch a swelling.]
   1. Any protuberant part; a round, swelling part or body; a
      knoblike process; as, a boss of wood.
      [1913 Webster]

   2. A protuberant ornament on any work, either of different
      material from that of the work or of the same, as upon a
      buckler or bridle; a stud; a knob; the central projection
      of a shield. See Umbilicus.
      [1913 Webster]

   3. (Arch.) A projecting ornament placed at the intersection
      of the ribs of ceilings, whether vaulted or flat, and in
      other situations.
      [1913 Webster]

   4. [Cf. D. bus box, Dan. b["o]sse.] A wooden vessel for the
      mortar used in tiling or masonry, hung by a hook from the
      laths, or from the rounds of a ladder. --Gwilt.
      [1913 Webster]

   5. (Mech.)
      (a) The enlarged part of a shaft, on which a wheel is
          keyed, or at the end, where it is coupled to another.
      (b) A swage or die used for shaping metals.
          [1913 Webster]

   6. A head or reservoir of water. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

boss
    adj 1: exceptionally good; "a boss hand at carpentry"; "his brag
           cornfield" [syn: boss, brag]
    n 1: a person who exercises control over workers; "if you want
         to leave early you have to ask the foreman" [syn:
         foreman, chief, gaffer, honcho, boss]
    2: a person responsible for hiring workers; "the boss hired
       three more men for the new job" [syn: boss, hirer]
    3: a person who exercises control and makes decisions; "he is
       his own boss now"
    4: a leader in a political party who controls votes and dictates
       appointments; "party bosses have a reputation for corruption"
       [syn: party boss, political boss, boss]
    5: a circular rounded projection or protuberance [syn: knob,
       boss]
    v 1: raise in a relief; "embossed stationery" [syn: emboss,
         boss, stamp]

Moby Thesaurus II by Grady Ward, 1.0:

334 Moby Thesaurus words for "boss":
   A per se, Big Brother, OK, ace, ace-high, administrator, anaglyph,
   ascendant, at the head, auditor, bad, bang-up, bas-relief,
   big cheese, bilge, blain, bleb, blister, blob, boatswain, bonzer,
   bow, bubble, bulb, bulge, bulla, bully, bump, bunch, burl,
   but good, button, bwana, cacique, cahot, cameo, cameo glass,
   capital, cavo-rilievo, champion, chaperon, chase, chef, chief,
   chieftain, chine, church dignitary, clump, coarsen, cock, colophon,
   command, commander, commanding, comptroller, concavity, condyle,
   control, controller, controlling, convex, convexity, cool, corking,
   crackerjack, cut glass, dactylogram, dactylograph, dandy, dean,
   delicious, dent, dint, direct, director, dominant, dominate,
   domineer, dowel, ducky, ear, ecclesiarch, elder, emboss,
   embossment, employer, excrescence, fab, famous, fine,
   fine and dandy, fingerprint, first-rate, flange, flap,
   floor manager, floorman, floorwalker, footmark, footprint,
   footstep, foreman, fossil footprint, fugleman, gaffer, gall,
   ganger, gear, general, genius, glyph, glyptograph, gnarl, goodman,
   governing, governor, granulate, great, groovy, guru, handle, head,
   headman, heavy, hegemonic, hegemonistic, hierarch, high relief,
   higher-up, hill, himself, honcho, horripilate, hot, hump, hunch,
   hunky-dory, husband, ichnite, ichnolite, impress, impression,
   imprint, in ascendancy, in charge, in chief, in the ascendant,
   indent, indentation, indention, inspector, intaglio,
   intaglio rilevato, intaglio rilievo, jam-up, jog, joggle,
   just dandy, keen, keep in order, keynoter, kingpin, knob, knot,
   knur, knurl, laureate, leader, leading, liege, liege lord, lip,
   loop, lord, lord it over, lord paramount, low relief, lump,
   man higher up, manage, manager, managing director, marvy, mask,
   master, mean, medal, medallion, mole, monitor, mountain, neat,
   nevus, nifty, nobby, noncommissioned officer, nonpareil, nub,
   nubbin, nubble, okay, order about, out of sight, overlook,
   overlord, overman, oversee, overseeing, overseer, owner, pad,
   padrone, papilloma, paragon, paramount, paterfamilias, patriarch,
   patron, paw print, pawmark, peachy, peachy-keen, peg, pimple,
   plaquette, policy maker, predominant, predominate, prepollent,
   preponderant, preponderate, prepotent, president, prevalent, prexy,
   principal, print, proctor, prodigy, proprietor, pug, pugmark,
   quarterback, rabbi, raise, regnant, regulating, regulative,
   regulatory, reigning, relief, relievo, rib, ride herd on, ridge,
   ring, ringleader, ripping, rough, rough up, roughen, ruler, ruling,
   rum, run, sachem, sahib, scrumptious, sculptured glass, seal,
   seigneur, seignior, senior, shoulder, sigil, signet, sirdar,
   slap-up, slave driver, smashing, solid, something else, sovereign,
   spiffing, spiffy, spine, stamp, stand over, standard-bearer, star,
   starets, step, straw boss, stud, stunning, style, subforeman,
   super, superintend, superintendent, superior, superman, superstar,
   supervise, supervising, supervisor, supervisory, supreme, survey,
   surveyor, swell, tab, take care of, take charge, taskmaster,
   teacher, the greatest, the most, thumbmark, thumbprint, top,
   top dog, tough, tubercle, tubercule, verruca, vesicle, vestige,
   virtuoso, visitor, wale, wart, welt, wizard



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

BOSS
       Basic OS Software for BASIC (OS, BASIC)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

BOSS
       BSI OSS Security Suite (BSI, OSS)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

BOSS
       Bus Owner/Supervisor/Selector (FireWire)


The Free On-line Dictionary of Computing (30 December 2018):

BOSS

   Bridgport Operating System Software.  A derivative of the ISO
   1054 numerical machine control language for milling, etc.