The triangle designates Major, but there is little need to put the triangle without adding the 7 since the absence of a triangle (C) assumes it is major. So the C triangle 7 is a short hand for CMaj7.

The C triangle 6 is the same as C6 but remember the C triangle 7 is not the same as a C7 which is a dominate chord.

The term major generally designates a triad of a root - third - fifth, versus the term minor which designates a triad of root - flat third - fifth. But Major or Minor does not tell you what the 6th or 7th is doing.

Are you really confused now?

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