em·bra·sure
noun/ɪmˈbreɪʒə(r)/
/ɪmˈbreɪʒər/
(architecture)- an opening in a wall for a door or window, wider on the inside than on the outside
斜面门（或窗）洞（两侧向内渐宽） Word Originearly 18th cent.: from French, from obsolete embraser (earlier form of ébraser) ‘widen a door or window opening’, of unknown ultimate origin.