Store capital raised in motor yacht (6)
I believe the answer is:
'store' is the definition.
(I know that store can be written as memory)
'capital raised in motor yacht' is the wordplay.
'capital' becomes 'Rome' (capital of Italy).
'raised' shows that the letters should be reversed in order (going up in a down clue).
'in' means one lot of letters goes inside another.
'motor yacht' becomes 'MY' (abbreviation for motor yacht).
'rome' reversed gives 'emor'.
'emor' placed within 'my' is 'MEMORY'.
(Other definitions for memory that I've seen before include "commemoration" , "Something remembered" , "See 23" , "Something recalled; part of computer" , "Power of recall" .)