Each note in any scale may be given a numerical label according to its position within the scale. The first note in the scale is considered the ‘root’ or the ‘tonic’. For example, in the C Major scale, C is the tonic, D is the ‘second’ degree’, E is the ‘third’ degree, F is the ‘fourth’ degree, G is the ‘fifth’ degree, A is the ‘sixth’ degree, B is the ‘seventh’ degree, and C is the ‘octave’.
Chord tones are notes extracted from scales in a specific order. Consider the first five notes in the C major scale (C,D,E,F,G). If you skip every other note between C and G, the sequence becomes: C-E-G. When these notes are sounded simultaneously, the result is a ‘C Major triad’. Note that the distance between C and E is equal to two ‘whole steps’ or four ‘half steps’ within the ‘chromatic’ scale. The distance between C (the root of the triad) and E (the third of the triad) insures that the ‘tonality’ of the triad is Major; however, if the third of the triad (E) is lowered by ½ step to Eb, the distance between the ‘interval’ is decreased to three ½ steps. In this case the tonality of the triad: C-Eb-G is referred to as ‘minor’. If the third (E) is raised ½ step (to the fourth to create the triad: C-F-G), the triad is considered ‘suspended’. A less common adjustment is to replace the third with a ‘second’: C-D-G. This is labeled C2 (not bb3) and known as a ‘retardation’. Western theory suggests all chords must have one of the above tonalities. This is not the case in jazz theory (or ‘applied’ theory). If 1-3-5-7 create the most basic chord qualities, 2-4-6 (an octave higher ) create the ‘extensions’: 9-11-13 (which are NOT considered in traditional western theory). The rules for ‘altered’ extensions, and which extensions are viable over given tonalities are involved to say the least. Also to be considered are ‘slash chords’.
The ‘fifth’ of any chord can be lowered or raised by ½ step, know respectively as ‘diminished’ or ‘augmented’. A flat fifth over a minor third creates a ‘diminished’ triad. Though the augmented fifth over a minor third is rare, an example is the iconic 007 James Bond theme by composer, John Barry.
Clearly, there are two separate systems of terminology used to supply labels for chord qualities. There are also a variety of nomenclatures and some are simply wrong. It will be to your advantage to develop an understanding of them all.