Building wing (3)
'building wing' is the definition.
(architectural term)
This is all the clue.
(Other definitions for ell that I've seen before include "Old measure of length about 45 inches" , "Former measure of length" , "Old measure equivalent to about 45 inches in England" , "Embellish with old measure of length" , "Extension" .)
'building wing' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for annex that I've seen before include "Add by conquest or occupation" , "Extension to a main building" , "Grab" , "Add as an extra part" , "Take by force" .)