PubDictionaries is a public-sourcing online database of dictionaries.
Here, a dictionary means a collection of pairs (text_expression, identifider).
If you have such a dictionary in a tabular format, e.g. TSV (tab-separeted values) or Exel, you can upload it on PubDictionaries, then you can immediately use REST services to lookup the dictionary, e.g. search for identifiders or text annotation.