Piece of glass left as rectangular design feature? (5)
I believe the answer is:
panel
'feature?' is the definition.
(I know that Panel is a feature)
'piece of glass left' is the wordplay.
'piece of glass' becomes 'pane' (I've seen this in another clue).
'left' becomes 'l' (common abbreviation).
'pane'+'l'='PANEL'
'as rectangular design' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for panel that I've seen before include "Bordered rectangle (in door etc)" , "Talk show group" , "Wall mounting" , "Instrument board; investigating group" , "Bordered rectangular area" .)