I am looking for the noun that is the thing that is either major or minor in respect to a chord such as a triad. I suppose it could also be an adjective. It would be 'x' in the following question: "What is the x of the GAB triad?".
EDIT: I meant to use a proper example triad such as 'GBD'... see comment below. I'm happy I made the mistake as I learned from that comment's explanation of what a GAB chord would be. :-)