physiology vs isotonic

physiology is a noun but isotonic is not a noun.

Word	Noun	Adjective	Verb	Adverb
physiology	Yes	No	No	No
isotonic	No	Yes	No	No

physiology (noun)	isotonic (noun)
processes and functions of an organism
the branch of the biological sciences dealing with the functioning of organisms

physiology (adjective)	isotonic (adjective)
	(used of solutions) having the same or equal osmotic pressure
	of or involving muscular contraction in which tension is constant while length changes
	relating to or characterized by the equal intervals of a musical scale
	of two or more muscles; having equal tension