Is there a difference between Scenario Testing and Functional Testing or are they synonymous?

So I'm looking into introducing a more extensive testing process and I was reading about Functional Testing. I've worked with Scenario Testing before, but I'm fairly new to the term Functional Testing.

It seems that the two are synonymous, however I've not been able to find any information on whether they are synonymous or whether one is a subcategory of the other or whether they are two separate things. I've searched on stackoverflow, I've read the wiki pages for both, I've read some blogs on both and some university pages on both and can't seem to find the answer.

So as the title says; is there a difference between Scenario Testing and Functional Testing or are they synonymous?