Scrivener for Windows has a number of writing tools available from the Tools menu, including options to look up selected words in a number of online references (dictionary, thesaurus, etc). These tools aren’t user definable, but if you are prepared to tinker a little under the hood there is a way to change these to something you use more regularly.
The steps below will switch the Dictionary.com and Thesaurus.com references to enable you to look up words in the Collins online dictionary and thesaurus instead (in particular, the American English versions).
1) Download the file Scrivener_en.qm from this link (you’ll need to unzip it), and save it to your hard drive.
2) Copy the file to the translations folder of your Scrivener installation (for example on my computer it’s C:\Program Files (x86)\Scrivener\translations\). Depending on the version of Scrivener you are running, you may already have a file called Scrivener_en.qm in that directory. It’s safe to overwrite it, but if you are extra cautious you could always make a backup first. The easiest way to do this is simply rename the original file Scrivener_en(BAK).qm, and then rename it back should you need to restore it at any point.
3) Launch Scrivener.
4) Go to Tools > Options in the menu system (or just press F12).
5) In the General tab of the Options dialog, change the Language to English.
6) Click OK in the information dialog that pops up.
7) Close and then relaunch Scrivener.
I have tested this modified file with Scrivener for Windows version 1.6.1 (the latest official release) as well as version 188.8.131.52 (the current beta). It should continue to work with future versions of WinScriv (unless the team at LitNLat make their own modifications to this part of the program), although you will need to reinstall the above linked file each time you upgrade.
As always, any thoughts, questions and enthusiastic praise should go in the comments section below.