work vs touch on

work is a noun but touch on is not a noun.

Word	Noun	Adjective	Verb	Adverb
work	Yes	No	Yes	No
touch on	No	No	Yes	No

As verbs, touch on is a hypernym of work; that is, touch on is a word with a broader meaning than work:

Other hypernyms of work include affect, bear on, bear upon, impact, touch.

work (noun)	touch on (noun)
activity directed toward making or doing something
the occupation for which you are paid
a product produced or accomplished through the effort or activity or agency of a person or thing
a place where work is done
the total output of a writer or artist (or a substantial part of it)
applying the mind to learning and understanding a subject (especially by reading)
(physics) a manifestation of energy; the transfer of energy from one physical system to another expressed as the product of a force and the distance through which it moves a body in the direction of that force

work (verb)	touch on (verb)
give a workout to	restore by replacing a part or putting together what is torn or broken
arrive at a certain condition through repeated motion	have an effect upon
go sour or spoil	refer to or discuss briefly
cause to undergo fermentation	be relevant to
find the solution to (a problem or question) or understand the meaning of
use or manipulate to one's advantage
to mix into a homogeneous mass
perform as expected when applied
move into or onto
shape, form, or improve a material
cause to happen or to occur as a consequence
prepare for crops
make something, usually for a specific function
gratify and charm, usually in order to influence
proceed along a path
move in an agitated manner
provoke or excite
be employed
cause to work
exert oneself by doing mental or physical work for a purpose or out of necessity; work
have an effect or outcome; often the one desired or expected
operate in a certain place, area, or specialty
proceed towards a goal or along a path or through an activity
have and exert influence or effect
operate in or through
cause to operate or function
behave in a certain way when handled