On piano, for example, a minute piece (8)
I believe the answer is:
particle
This could be a double definition.
'on piano for example' is the first definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'a minute piece' is the second definition.
(I've seen this before)
Can you help me to learn more?
(Other definitions for particle that I've seen before include "Small piece of matter" , "Tiny piece of anything" , "Minute fragment" , "Crumb" , "Molecule" .)