piano action vs damper block

piano action and damper block both are nouns.

Word	Noun	Adjective	Verb	Adverb
piano action	Yes	No	No	No
damper block	Yes	No	No	No

piano action (noun)	damper block (noun)
action consisting of a system of levers that move a felt hammer to strike the strings when a key is depressed	damper consisting of a small felted block that drops onto a piano string to stop its vibration