tending vs pet sitting

tending and pet sitting both are nouns.

Word	Noun	Adjective	Verb	Adverb
tending	Yes	Yes	No	No
pet sitting	Yes	No	No	No

As nouns, pet sitting is a hyponym of tending; that is, pet sitting is a word with a more specific, narrower meaning than tending:

tending: the work of providing treatment for or attending to someone or something
pet sitting: the work of a pet sitter; caring for pets in their own home while their owners are away from home

tending (noun)	pet sitting (noun)
the work of providing treatment for or attending to someone or something	the work of a pet sitter; caring for pets in their own home while their owners are away from home

tending (adjective)	pet sitting (adjective)
(usually followed by `to') naturally disposed toward