M3U1L1L1I1O1N1S1
10 points
MULLIONS is validvalid
MULLION, to provide with vertical dividing strips [v]
MULLION, to provide the upright division between the panes of a window [v]
MULLION, to provide with vertical dividing strips [v]
MULLION, to provide the upright division between the panes of a window [v]