Source : Webster's Revised Unabridged Dictionary (1913)

Recognize \Rec"og*nize\, v. i. (Law)
   To enter an obligation of record before a proper tribunal;
   as, A, B recognized in the sum of twenty dollars. [Written
   also {recognise}.]

   Note: In legal usage in the United States the second syllable
         is often accented.

Recognize \Rec"og*nize\, v. t. [imp. & p. p. {Recognized}; p.
   pr. & vb. n. {Recognizing}.] [From {Recognizance}; see
   {Cognition}, and cf. {Reconnoiter}.] [Written also
   {recognise}.]
   1. To know again; to perceive the identity of, with a person
      or thing previously known; to recover or recall knowledge
      of.

            Speak, vassal; recognize thy sovereign queen.
                                                  --Harte.

   2. To avow knowledge of; to allow that one knows; to consent
      to admit, hold, or the like; to admit with a formal
      acknowledgment; as, to recognize an obligation; to
      recognize a consul.

   3. To acknowledge acquaintance with, as by salutation,
      bowing, or the like.

   4. To show appreciation of; as, to recognize services by a
      testimonial.

   5. To review; to re["e]xamine. [Obs.] --South.

   6. To reconnoiter. [Obs.] --R. Monro.

   Syn: To acknowledge; avow; confess; own; allow; concede. See
        {Acknowledge}.

Source : WordNet®

recognise
     v 1: show approval or appreciation of; "My work is not recognized
          by anybody!"; "The best student was recognized by the
          Dean" [syn: {recognize}]
     2: grant credentials to; "The Regents officially recognized the
        new educational institution"; "recognize an academic
        degree" [syn: {accredit}, {recognize}]
     3: detect with the senses; "The fleeing convicts were picked
        out of the darkness by the watchful prison guards"; "I
        can't make out the faces in this photograph" [syn: {recognize},
         {distinguish}, {discern}, {pick out}, {make out}, {tell
        apart}]
     4: express greetings upon meeting someone [syn: {greet}, {recognize}]
     5: express obligation, thanks, or gratitude for; "We must
        acknowledge the kindness she showed towards us" [syn: {acknowledge},
         {recognize}]
     6: be fully aware or cognizant of [syn: {recognize}, {realize},
         {realise}, {agnize}, {agnise}]
     7: perceive to be the same [syn: {recognize}]
     8: accept (someone) to be what is claimed or accept his power
        and authority; "The Crown Prince was acknowledged as the
        true heir to the throne"; "We do not recognize your gods"
        [syn: {acknowledge}, {recognize}, {know}]