closed stringer（封闭式斜梁）是什么意思？音标发音+图解场景

封闭式斜梁 /ˈkləʊzd ˈstɹɪŋə/ n

English: closed stringer · 封闭式斜梁

释义：Diagonal piece of notched wood supporting steps and risers and enclosing their ends.

这个词出现在以下图解场景（1）