The Meaning of the Name "Tate" & "Thaddeus"

I was interested in what the name 'Tate' meant, so I started googling, the common consensus among most of the baby-naming websites I ended up at, was Tate meant 'cheerful' of all things.

Then I came across this website... and found: 

Interesting that one of the roughly similar names is Thad. Thad obviously derives from Thaddeus, which is the real name of our crazy monster in the basement. 

Ok, so what does Thaddeus mean?

It's derived from the Greek word "thaddai" meaning "Heart" apparently. Interesting considering the monster has the heart of a once-living being. The other meaning-possibility is that it is derivation of 'Theodore' which is interpreted to mean "God's gift." Think there's a bit of loaded meaning on his name??

'Tate' and 'Thaddeus' sounded a bit too similar for them not to mean something -- I'm really hoping that we find out exactly what the connection between Tate and the infantata is before the end of the season. There's got to be something serious there, lol.