society > inhabiting and dwelling > inhabited place > a building > parts of building > window or door > parts of windows > [noun] > glazing or dividing bar > part of (3)
core1663
spec. The central portion of a window-lead or came connecting the leaf or part overlapping the edges of the glass.
storey1811
Architecture. Each of a number of rows of columns, windows, etc., positioned one above the other.
beginner1886
Architecture. The lower part of a mullion worked on the stone forming the sill.