Remark about some section (11)
I believe the answer is:
compartment
'section' is the definition.
(I have seen 'Separate section ' mean 'compartment' so perhaps 'section' could also mean 'compartment')
'remark about some' is the wordplay.
'remark' becomes 'comment' (commenting is a kind of remarking).
'about' means one lot of letters goes inside another.
'some' becomes 'part' (only part of something).
'comment' going around 'part' is 'COMPARTMENT'.
(Other definitions for compartment that I've seen before include "Division of rail carriage" , "Separated section" , "Section of railway carriage etc" , "Divide into separate sections" , "Box" .)