Wordnet 3.0
NOUN (1)
1. 
 location of a colony of the United Kingdom on a limestone promontory at the southern tip of Spain; 
 strategically important because it can control the entrance of ships into the Mediterranean; 
 one of the Pillars of Hercules; 
[syn: Gibraltar, Rock of Gibraltar, Calpe]
WordNet (r) 3.0 (2006):
Rock of Gibraltar
    n 1: location of a colony of the United Kingdom on a limestone
         promontory at the southern tip of Spain; strategically
         important because it can control the entrance of ships into
         the Mediterranean; one of the Pillars of Hercules [syn:
         Gibraltar, Rock of Gibraltar, Calpe]