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]