Can someone please define, in simplest linguistic form, what the #1 chord is with no relativity to a key. #1 of what? The first (#1) note in a scale? If that is the case, the #1 chord in C, being C, means the #1 chord is C.

Mario then said " If you are talking about chord progressions and the key signature is F then the C7 is the 5th chord and F is the #1 chord."

Well, nobody said anything about chord progressions, and the key mentioned in the original post was C. Thus C should be the #1 chord.

Also, it would be a good thing to not use pronouns like "it".

Mario said "As mentioned previously what is a #1 chord? If you are talking just chords then yes it is the #1 chord." What is the IT you are referring back to? If we are talking scales as the base to create chords, we are talking notes at that point, way short of chords having yet be created. This is why I am so confused by the #1 chord thing.

Again, someone please define #1 chord if that term does NOT mean "The chord created with the first note of the scale as the root note." I can't see any way that F would be the #1 anything in the key of C. That comment was is the first reply after the OP and I have been trying since to get a definition of what "the #1 chord" is. Very confusing.