business vs treadmill

business and treadmill both are nouns.

Word	Noun	Adjective	Verb	Adverb
business	Yes	No	No	No
treadmill	Yes	No	No	No

As nouns, treadmill is a hyponym of business; that is, treadmill is a word with a more specific, narrower meaning than business:

business (noun)	treadmill (noun)
the principal activity in your life that you do to earn money	a job involving drudgery and confinement
the activity of providing goods and services involving financial and commercial and industrial aspects	a mill that is powered by men or animals walking on a circular belt or climbing steps
the volume of commercial activity	an exercise device consisting of an endless belt on which a person can walk or jog without changing place
incidental activity performed by an actor for dramatic effect
an immediate objective
a rightful concern or responsibility
a commercial or industrial enterprise and the people who constitute it
customers collectively
business concerns collectively