'Some', we hear, actually means the lot (3)
I believe the answer is:
sum
'the lot' is the definition.
(thesaurus)
'some we hear' is the wordplay.
'we hear' shows a homophone (sound like).
'some' sounds like 'SUM'.
'actually means' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for sum that I've seen before include "Total, add" , "Amount of money; add" , "pupils find it a problem" , "Arithmetical problem" , "Arithmetic calculation" .)