The Collaborative International Dictionary of English v.0.48:

Signalize \Sig"nal*ize\, v. t. [imp. & p. p. Signalized; p.
   pr. & vb. n. Signalizing.] [From Signal, a.]
   1. To make signal or eminent; to render distinguished from
      what is common; to distinguish.
      [1913 Webster]

            It is this passion which drives men to all the ways
            we see in use of signalizing themselves. --Burke.
      [1913 Webster]

   2. To communicate with by means of a signal; as, a ship
      signalizes its consort.
      [1913 Webster]

   3. To indicate the existence, presence, or fact of, by a
      signal; as, to signalize the arrival of a steamer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

signalize
    v 1: provide with traffic signals; "signalize a busy
         intersection" [syn: signalize, signalise]
    2: communicate silently and non-verbally by signals or signs;
       "He signed his disapproval with a dismissive hand gesture";
       "The diner signaled the waiters to bring the menu" [syn:
       sign, signal, signalize, signalise]
    3: point out carefully and clearly [syn: signalize,
       signalise, point out, call attention]
    4: make conspicuous or noteworthy [syn: signalize,
       signalise, distinguish]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "signalize":
   adorn, approve, argue, attest, beat the drum, bespeak,
   bestow honor upon, betoken, blow the trumpet, breathe, celebrate,
   commemorate, confer distinction on, connote, demonstrate, denote,
   dignify, dip, display, distinguish, dress ship, evidence, evince,
   exchange colors, exhibit, express, fire a salute, flag, flag down,
   flash, furnish evidence, gesture, give a signal,
   give indication of, give the nod, glance, go to show, grace, hail,
   hail and speak, half-mast, hallow, hoist a banner, hold jubilee,
   honor, illustrate, imply, indicate, individualize, individuate,
   involve, jubilate, jubilize, keep, kick, leer, maffick,
   make a sign, make merry, manifest, mark, memorialize, motion, nod,
   nudge, observe, point to, poke, qualify, raise a cry, salute,
   set forth, show, show signs of, sign, signal, signify, solemnize,
   solemnly mark, sound a fanfare, sound an alarm, sound the trumpet,
   speak, speak for itself, speak volumes, suggest, symptomatize,
   tell, tend to show, touch, unfurl a flag, wave, wave a flag,
   wave the hand, wink