Searching for dictionaries in the online library catalog is best done using the advanced search.
For example, to search for a dictionary in Urdu, use Urdu or Urdu Language as a subject and dictionary as another subject. If looking for a dictionary that uses a language other than English, be sure to include that language as a subject term as well.
Be sure to check the location carefully. Some dictionaries are kept in the Reference collections of libraries and only allowed to be used within the library.