The Collaborative International Dictionary of English v.0.48:

Cebu \Cebu\ prop. n.
   1. one of the Visayan islands of the central Philippines,
      important for its fine harbor.
      [WordNet 1.5]

   2. an important seaport on the Island of Cebu in the
      Philippines.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

Cebu
    n 1: an important seaport on the island of Cebu in the
         Philippines [syn: Cebu, Cebu City]
    2: one of the Visayan islands of the central Philippines;
       important for its fine harbor