@user45266 It might also be consider a chromatic mediant or chromatically-altered mediant. Whenever you tweak the III (aka mediant) or VI (aka submediant).

hey guys whats the name of the chord in the key of C major with the intervals tritone and a perfect 5th aka C - F# - G?

@Seery Some folks like to call that sus♯4. If I had to give a chord symbol, that's what I'd write (because just about any musician would know what I meant), but to me, it's usually more useful to just call it a "lydian chord" when I don't have to be too specific. There are plenty of lydian chords, this is just one example of one.

Many thanks for clarifying!!