QUALITY n.
as it is; anything belonging to a subject, or predicable of it; distinguishing property, characteristic, or attribute; peculiar power, capacity, or virtue; distinctive trait; as, the tones of a flute differ from those of a violin in quality; the great quality of a statesman.
RADICAL n.
A characteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom. As a general rule, the metallic atoms are basic radicals, while the nonmetallic atoms are acid radicals. J. P. Cooke.