Dictionary management
One of the most significant feature of the Goldendict is its dictionary management capabilities. You can add offline/online/sound/morphology dictionaries and group them according to your preferences.
Open the Goldendict application, go to Edit->dictionaries.
A new pop-up window will be displayed with various tabs and options. Under the 'Sources' tab, you can find the 'Files' section (This section is what you see by default)
On the right hand side you can see "add/remove/rescan" options. Click on the 'Add' button browse to the folder where you have stored your Goldendict dictionary files. You can also select the 'Recursive' option if you have your dictionaries in separate sub-folders.
Finally click on the 'Rescan now' button. Your dictionaries will now be added and indexed by the GoldenDict.
Go to Edit -> Dictionaries... -> Sources -> Websites, click Add on the right to add a web source. The format varies between different websites. For merriam-webster, you can add an address like the following
https://www.merriam-webster.com/dictionary/%GDWORD%
Give it a name, for example, Merriam-webster. Then tick on the Enabled button on the left.