/mul"yeuhn/ , Archit.
n.
1. a vertical member, as of stone or wood, between the lights of a window, the panels in wainscoting, or the like.
2. one of the radiating bars of a rose window or the like.
v.t.
3. to furnish with, or to form into divisions by the use of, mullions.
[ 1560-70; metathetic var. of MONIAL ]