What term describes a short vertical or horizontal piece of wood used to hold a pane of glass?

The term that describes a short vertical or horizontal piece of wood used to hold a pane of glass is called a muntin. Muntins are specifically designed to separate and hold individual panes of glass within a window frame. They serve both functional and aesthetic purposes, allowing for greater control over the size and arrangement of the glass while contributing to the overall design of the window.

In contrast, a mullion strip refers to a vertical or horizontal structural element that divides two adjacent window units but does not necessarily hold glass itself. A screen is typically a barrier made of a mesh that keeps insects out while allowing airflow but does not pertain to glass holding. A sash is a framework that holds the glass panes and is part of the window, but it consists of larger components that encompass multiple glass panes rather than the individual dividers that muntins represent. Thus, the correct answer effectively identifies the role of muntins in window construction.