Source : Webster's Revised Unabridged Dictionary (1913)

Extend \Ex*tend"\, v. t. [imp. & p. p. {Extended}; p. pr. & vb.
   n. {Extending}.] [L. extendere, extentum, extensum; ex out +
   tendere to stretch. See {Trend}.]
   1. To stretch out; to prolong in space; to carry forward or
      continue in length; as, to extend a line in surveying; to
      extend a cord across the street.

            Few extend their thoughts toward universal
            knowledge'.                           --Locke.

   2. To enlarge, as a surface or volume; to expand; to spread;
      to amplify; as, to extend metal plates by hammering or
      rolling them.

   3. To enlarge; to widen; to carry out further; as, to extend
      the capacities, the sphere of usefulness, or commerce; to
      extend power or influence; to continue, as time; to
      lengthen; to prolong; as, to extend the time of payment or
      a season of trail.

   4. To hold out or reach forth, as the arm or hand.

            His helpless hand extend.             --Dryden.

   5. To bestow; to offer; to impart; to apply; as, to extend
      sympathy to the suffering.

   6. To increase in quantity by weakening or adulterating
      additions; as, to extend liquors. --G. P. Burnham.

   7. (Eng. Law) To value, as lands taken by a writ of extent in
      satisfaction of a debt; to assign by writ of extent.

   {Extended letter} (Typog.), a letter, or style of type,
      having a broader face than is usual for a letter or type
      of the same height.

   Note: This is extended type.

   Syn: To increase; enlarge; expand; widen; diffuse. See
        {Increase}.

Source : WordNet®

extend
     v 1: extend in scope or range or area; "The law was extended to
          all citizens"; "widen the range of applications";
          "broaden your horizon"; "Extend your backyard" [syn: {widen},
           {broaden}]
     2: stretch out over a distance, space, time, or scope; run or
        extend between two points or beyond a certain point;
        "Service runs all the way to Cranbury"; "His knowledge
        doesn't go very far"; "My memory extends back to my fourth
        year of life"; "The facts extend beyond a consideration of
        her personal assets" [syn: {run}, {go}, {pass}, {lead}]
     3: span an interval of distance, space or time; "The war
        extended over five years"; "The period covered the turn of
        the century"; "My land extends over the hills on the
        horizon"; "This farm covers some 200 acres" [syn: {cover}]
     4: make available; provide; "extend a loan"; "The bank offers a
        good deal on new mortgages" [syn: {offer}]
     5: thrust or extend out; "He held out his hand"; "point a
        finger"; "extend a hand"; "the bee exserted its sting"
        [syn: {exsert}, {stretch out}, {put out}, {hold out}, {stretch
        forth}]
     6: reach outward in space; "The awning extends several feet
        over the sidewalk" [syn: {poke out}, {reach out}]
     7: offer verbally; "extend my greetings"; "He offered his
        sympathy" [syn: {offer}]
     8: extend one's limbs or muscles, or the entire body; "Stretch
        your legs!"; "Extend your right arm above your head" [syn:
         {stretch}]
     9: expand the influence of; "The King extended his rule to the
        Eastern part of the continent" [syn: {expand}]
     10: lengthen in time; cause to be or last longer; "We prolonged
         our stay"; "She extended her visit by another day"; "The
         meeting was drawn out until midnight" [syn: {prolong}, {protract},
          {draw out}]
     11: extend or stretch out to a greater or the full length;
         "Unfold the newspaper"; "stretch out that piece of
         cloth"; "extend the TV antenna" [syn: {unfold}, {stretch},
          {stretch out}]
     12: cause to move at full gallop; "Did you gallop the horse just
         now?" [syn: {gallop}]
     13: open or straighten out; unbend; "Can we extend the legs of
         this dining table?"
     14: use to the utmost; exert vigorously or to full capacity; "He
         really extended himself when he climbed Kilimanjaro";
         "Don't strain your mind too much" [syn: {strain}]
     15: prolong the time allowed for payment of; "extend the loan"
     16: continue or extend; "The civil war carried into the
         neighboring province"; "The disease extended into the
         remote mountain provinces" [syn: {carry}]
     17: increase in quantity or bulk by adding a cheaper substance;
         "stretch the soup by adding some more cream"; "extend the
         casserole with a little rice" [syn: {stretch}]

Source : Free On-Line Dictionary of Computing

extend
     
         To add {features} to a program, especially
        through the use of {hooks}.
     
        "Extend" is very often used in the phrase "extend the
        {functionality} of a program."
     
        {Plug-ins} are one form of extension.
     
        (1997-06-21)