What geometric terms that start with j?

One geometric term that starts with "J" is "juxtaposition," which refers to the act of placing two or more geometric figures, shapes, or objects side by side or close together for comparison or contrast. Another term is "joint," which is the point where two or more geometric elements, such as lines or shapes, meet or connect. Additionally, "jacobian" is a mathematical concept in geometry that relates to the determinant of the Jacobian matrix, which describes the rate at which a change in one set of variables affects another set of variables in a geometric transformation.