isotonic vs physiology

isotonic is not a noun while physiology is a noun.

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

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

isotonic (adjective)	physiology (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