isometric vs isotonic

isometric is a noun but isotonic is not a noun.

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

isometric (noun)	isotonic (noun)
a line connecting isometric points

isometric (adjective)	isotonic (adjective)
of or involving muscular contraction in which tension increases while length remains constant	(used of solutions) having the same or equal osmotic pressure
related by an isometry	of or involving muscular contraction in which tension is constant while length changes
of a crystal system characterized by three equal axes at right angles	relating to or characterized by the equal intervals of a musical scale
having equal dimensions or measurements	of two or more muscles; having equal tension