Is there a name for a matrix which is a multiple of an orthogonal matrix? I.e. a square matrix $A$ which satisfies the condition
$$A^TA = AA^T = \lambda I$$
where $\lambda$ is some scalar (which should perhaps be required to be non-zero) and $I$ is the identity matrix. Or in other words, a matrix whose rows and columns are orthogonal vectors of equal length $\sqrt\lambda$, but not neccessarily unit length, so not orthonormal.
I've thought about these objects twice in different contexts recently, and it feels like a concept that should have a name. So far I haven't been able to find such a name, though. Do you know an established name for these matrices?