1. A method comprising: matching a token from at least a portion of a text string with a matching concept in an ontology; identifying a first concept as being hierarchically related to the matching concept within the ontology; identifying a second concept as being hierarchically related to the first concept within the ontology; including the first and second concepts in a set of features of the token; and determining, using at least one processor, a measure related to a likelihood that the at least a portion of the text string corresponds to a particular entity type, based at least in part on the set of features of the token.