Architecturally, outer parts of a domicile (4)

I believe the answer is:

dome

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'architecturally outer parts of a domicile' is the definition.
I can't tell whether this defines the answer.

'architecturally outer parts of a domicile' is the wordplay.
'architecturally' becomes 'do' (I can't explain this - if you can you should believe this answer much more).
'outer parts of' means to remove the middle letters.
'a domicile' becomes 'messuage' (messuage is a kind of domicile).
'messuage' with its middle taken out is 'me'.
'do'+'me'='DOME'

Can you help me to learn more?

(Other definitions for dome that I've seen before include "Mode or arched roof" , "Hemispherical roof" , "Cupola - millennium building" , "Head" , "Curved roof" .)

I've seen this clue in the Evening Standard.

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