Source : Webster's Revised Unabridged Dictionary (1913)

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.

   2. To perform the arithmetical operation of addition; as, he
      adds rapidly.

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).

            The Lord shall add to me another son. --Gen. xxx.
                                                  24.

Source : WordNet®

ADD
     n : a condition (mostly in boys) characterized by behavioral and
         learning disorders [syn: {attention deficit disorder}, {attention
         deficit hyperactivity disorder}, {ADHD}, {hyperkinetic
         syndrome}, {minimal brain dysfunction}, {minimal brain
         damage}, {MBD}]