Online lookup from editor
It should be easy to add context menu entries for looking up words and selections online. For instance, for single words, formatting a lookup URL to an online dictionary is possible. For selected text, perhaps a lookup in a search engine is also a useful option.
These are pretty easy to implement. All that is needed is a small GUI to set up the entries, perhaps with a few defaults pre-defined. An example for a lookup URL for single words could be:
Merriam Webster: https://www.merriam-webster.com/dictionary/{word}
Where {word} would be replaced with the selected word. The URL can then be opened in the OS' default browser.
There are various approaches to making the settings, but the simplest is a Name/URL list where the user can check/uncheck the ones they want to show up in the editor context menu and add their own. The list should be filled in with a few default options. They should be divided into two categories: "Look up in" and "Search with".