The term gospel chords generally refers to certain ways of playing any of the many basic chords that one is likely to hear when listening to gospel music. The way these chords are voiced is really what constitutes them as "gospel chords."
"Voicing" chords is basically taking basic chords and rearranging the chords tones to create different "sound textures."
There are many resources available when it comes to learning more about gospel chords and you are encouraged to pursue them. This is a topic that is sure to lead you to a gold mine of knowledge when it comes to learning all about chords in general...
You are absolutely encouraged, first, to get a handle on your basic 7th chords on the piano. One tool that is becoming universally popular
is this one
since it really gets you to master 7th chords in a most easy manner.