  Understanding the semantic relationships between terms is a fundamental task
in natural language processing applications. While structured resources that
can express those relationships in a formal way, such as ontologies, are still
scarce, a large number of linguistic resources gathering dictionary definitions
is becoming available, but understanding the semantic structure of natural
language definitions is fundamental to make them useful in semantic
interpretation tasks. Based on an analysis of a subset of WordNet's glosses, we
propose a set of semantic roles that compose the semantic structure of a
dictionary definition, and show how they are related to the definition's
syntactic configuration, identifying patterns that can be used in the
development of information extraction frameworks and semantic models.
