Erect articulated beams (4)
I believe the answer is:
rays
'beams' is the definition.
(I've seen this before)
'erect articulated' is the wordplay.
'erect' becomes 'raise' ('raise' can be a synonym of 'erect').
'articulated' shows a homophone (sound like).
'raise' is a homophone of 'RAYS'.
(Other definitions for rays that I've seen before include "Columns of light or heat" , "Pencils of light" , "Single lines of light" , "Beams of sunlight" , "Beams - fish" .)