Di‐ag″o‐nal (?), n. 1. A right line drawn from one angle to another not adjacent, of a figure of four or more sides, and dividing it into two parts.
2. (Engin.) A member, in a framed structure, running obliquely across a panel.
3. A diagonal cloth; a kind of cloth having diagonal stripes, ridges, or welts made in the weaving.