The Collaborative International Dictionary of English v.0.48:

Add \Add\, v. t. [imp. & p. p. Added; p. pr. & vb. n.
   Adding.] [L. addere; ad + dare to give, put. Cf. Date,
   Do.]
   1. To give by way of increased possession (to any one); to
      bestow (on).
      [1913 Webster]

            The Lord shall add to me another son. --Gen. xxx.
                                                  24.
      [1913 Webster]

   2. To join or unite, as one thing to another, or as several
      particulars, so as to increase the number, augment the
      quantity, enlarge the magnitude, or so as to form into one
      aggregate. Hence: To sum up; to put together mentally; as,
      to add numbers; to add up a column.
      [1913 Webster]

            Back to thy punishment,
            False fugitive, and to thy speed add wings.
                                                  --Milton.
      [1913 Webster]

            As easily as he can add together the ideas of two
            days or two years.                    --Locke.
      [1913 Webster]

   3. To append, as a statement; to say further.
      [1913 Webster]

            He added that he would willingly consent to the
            entire abolition of the tax.          --Macaulay.
      [1913 Webster]

   Syn: To Add, Join, Annex, Unite, Coalesce.

   Usage: We add by bringing things together so as to form a
          whole. We join by putting one thing to another in
          close or continuos connection. We annex by attaching
          some adjunct to a larger body. We unite by bringing
          things together so that their parts adhere or
          intermingle. Things coalesce by coming together or
          mingling so as to form one organization. To add
          quantities; to join houses; to annex territory; to
          unite kingdoms; to make parties coalesce.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Add \Add\, v. i.
   1. To make an addition. To add to, to augment; to increase;
      as, it adds to our anxiety. "I will add to your yoke." --1
      Kings xii. 14.
      [1913 Webster]

   2. To perform the arithmetical operation of addition; as, he
      adds rapidly.
      [1913 Webster]

WordNet (r) 3.0 (2006):

ADD
    n 1: a condition (mostly in boys) characterized by behavioral
         and learning disorders [syn: attention deficit disorder,
         ADD, attention deficit hyperactivity disorder, ADHD,
         hyperkinetic syndrome, minimal brain dysfunction,
         minimal brain damage, MBD]
    v 1: make an addition (to); join or combine or unite with
         others; increase the quality, quantity, size or scope of;
         "We added two students to that dorm room"; "She added a
         personal note to her letter"; "Add insult to injury"; "Add
         some extra plates to the dinner table" [ant: take away,
         take out]
    2: state or say further; "`It doesn't matter,' he supplied"
       [syn: add, append, supply]
    3: bestow a quality on; "Her presence lends a certain cachet to
       the company"; "The music added a lot to the play"; "She
       brings a special atmosphere to our meetings"; "This adds a
       light note to the program" [syn: lend, impart, bestow,
       contribute, add, bring]
    4: make an addition by combining numbers; "Add 27 and 49,
       please!" [syn: add, add together] [ant: deduct,
       subtract, take off]
    5: determine the sum of; "Add all the people in this town to
       those of the neighboring town" [syn: total, tot, tot
       up, sum, sum up, summate, tote up, add, add
       together, tally, add up]
    6: constitute an addition; "This paper will add to her
       reputation"

Moby Thesaurus II by Grady Ward, 1.0:

102 Moby Thesaurus words for "add":
   adjoin, affix, agglutinate, algebraize, amalgamate, annex, append,
   assimilate, attach, augment, blend, burden, calculate, cast,
   cipher, clutter, coalesce, combine, come together, complicate,
   compound, comprise, compute, conjoin, connect, consolidate, cumber,
   decorate, divide, dope out, embody, encompass, encumber, enlarge,
   estimate, extract roots, fasten, figure, figure in, figure out,
   flux, foot, fuse, glue on, hitch on, include, incorporate,
   increase, infix, integrate, interblend, interfuse, join, join with,
   lump together, make one, measure, meld, melt into one, merge, mix,
   multiply, ornament, paste on, plus, postfix, prefix, put together,
   put with, reckon, reembody, roll into one, saddle, saddle with,
   score, shade into, slap on, solidify, subjoin, subtract, suffix,
   sum, summate, superadd, superimpose, superpose, syncretize,
   syndicate, synthesize, tack on, tag, tag on, take account of,
   take on, tally, tot, total, tote, unify, unite, unite with,
   work out



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

ADD
       Adapter Device Driver (OS/2)


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

ADD
       AGP Digital Display [adapter] (AGP)