Dynamic dictionary based on context

In some implementations, a user of an electronic device may select a term of one or more words from the text of a displayed digital work. In response, a dictionary module may select a particular dictionary to access from among a plurality of dictionaries available on the electronic device. For example, based at least in part on metadata corresponding to the displayed digital work, the dictionary module may select a dictionary to access from a hierarchy of dictionaries. The dictionary module may present a definition obtained from the selected dictionary in a dictionary interface displayed over the presentation of the digital work. Further, the dictionary module may identify a location of at least one other occurrence of the selected term in the digital work or in a different digital work, and may display an excerpt of text including the at least one other occurrence of the selected term.