In looking at triads and seventh chords, we have only learned how to label and classify these muiscal objects without specifying a particular root. A major triad or a dominant seventh chord can be built off any of the twelve pitch-classes, and each of the pitch-classes have multiple options depending on which enharmonic equivalent you choose as the root.
There is one commonly-used method that we allows us to label specific triads and seventh chords as well as their inversions: leadsheet notation. This is also sometimes referred to as slash-chord notation, jazz chord symbols, or pop chord symbols. This system for labeling chords is prevalent in jazz and pop music but is extremely useful to all musicians because it creates a reliable way to communicate chords of any complexity in a concise manner.
Even after we introduce Roman numeral analysis and harmonic function in Unit 6,we will use leadsheet notation to provide a harmonic overview of complex analyses before we try to assign harmonic function and relationships. For example, if we have a C major triad and an F major triad and no other context, we cannot be sure what key this is. For those with a knowledge of diatonic function, it would seem most likely that these two chords belong to F major, but they could also exist diatonically in the keys of C major, D minor, A minor, as well as various modes. When analyzing harmonically ambiguous functions, it is critical to have a shorthand for labeling chords, so that we can look at the overview rather than re-analyzing each chord every time we come to a section of music.