[1] : The Collaborative International Dictionary of English v.0.48

plus \plus\, a. l., more; akin to gr. ?, ?, and e. full. see
   full, a., and cf. pi`u, pleonasm.
   1913 webster
   1. math. more, required to be added; positive, as
      distinguished from negative; -- opposed to minus.
      1913 webster

   2. hence, in a literary sense, additional; real; actual.
      1913 webster

            success goes invariably with a certain plus or
            positive power.                       --emerson.
      1913 webster

   plus sign math., the sign + which denotes addition, or
      a positive quantity.
      1913 webster
see also:
full pi`u pleonasm minus plus sign 

[2] : WordNet (r) 2.0

plus
     adj 1: on the positive side or higher end of a scale; "a plus
            value"; "temperature of plus 5 degrees"; "a grade of c
            plus" ant: minus
     2: involving advantage or good; "a plus or positive factor"
        syn: positive
     n 1: a useful or valuable quality syn: asset ant: liability
     2: the arithmetic operation of summing; calculating the sum of
        two or more numbers; "the summation of four and three
        gives seven"; "four plus three equals seven" syn: summation,
         addition
see also:
minus positive asset liability summation addition 

[3] : Moby Thesaurus II by Grady Ward, 1.0

146 moby thesaurus words for "plus":
   above, accessory, add, added, added to, addend, addition,
   additional, additionally, adjoin, advantage, affix, again,
   agglutinate, aggrandize, all included, along with, also,
   altogether, among other things, ancillary, and, and all, and also,
   and so, annex, another, append, as well, as well as, asset, attach,
   attended by, au reste, augment, auxiliary, balance, beef up,
   benefit, beside, besides, beyond, bonus, boost, build, burden,
   collateral, complicate, compound, conjoin, contributory,
   coupled with, decorate, dividend, else, en plus, encumber, enlarge,
   expand, extra, farther, for lagniappe, fresh, further, furthermore,
   gain, glue on, gratuity, hitch on, in addition, in addition to,
   in conjunction with, including, inclusive of, infix, inter alia,
   into the bargain, item, join with, lagniappe, leftover, let alone,
   likewise, linked to, magnify, margin, minus, more, moreover,
   negative, new, not to mention, on the side, on top of, ornament,
   other, over, over and above, overage, overmeasure, overplus,
   overrun, overset, overstock, oversupply, paste on, plus sign,
   positive, postfix, pourboire, prefix, profit, put with, remainder,
   return, saddle with, similarly, slap on, something extra, spare,
   subjoin, subtotal, suffix, sum, summation, superadd, supernumerary,
   superpose, supplemental, supplementary, surplus, surplusage,
   tack on, tag, tag on, then, therewith, tip, to boot, together with,
   too, total, ulterior, unite with, with, yet

[4] : The Free On-line Dictionary of Computing (27 SEP 03)

plus
     
        late 60's.  machine-oriented systems language used internally
        by univac.
     
     

[5] : The Free On-line Dictionary of Computing (27 SEP 03)

plus
     
        +
     
        common: itu-t: plus; add.  rare: cross; intercal:
        intersection.
     
     
see also:
itu-t intercal 

Plus >> P Words
Plus, definition of term: Plus
plus_pag1.html

Ne Plus Ultra >> N Words
Ne Plus Ultra, definition of term: Ne Plus Ultra
ne+plus+ultra_pag1.html