What's a pseudo-rotation? I'm sorry for this lexical, probably extremely elementary, question. But what is a pseudo-rotation? I just read this term for the first time, in the beginning of the 4th chapter book of CFT by Di Francesco & al. I would say it may be an hyperbolic rotation or a rotation followed by a parity operation (with determinant equals to -1).
Couldn't find it on google, so it doesn't seem to be a standard terminology, otherwise please forgive my ignorance.
 A: I) Recall that the $d$-dimensional (homogeneous) Lorentz group is $O(d-1,1)$. Also recall that $O(d)$  is the orthogonal group, and $SO(d)$  is the group of (proper) rotations. 
More generally, since a manifold $(M,g)$ equipped with a metric $g$ of signature $(p,q)$ is called a pseudo-Riemannian manifold, it is natural to call $O(p,q)$ the pseudo-orthogonal group and call $SO(p,q)$ the group of pseudo-rotations. In other words, the prefix pseudo refers here to that $p$ or $q$ are not zero.
II) Note that in the same setting of $O(d)$, $O(d-1,1)$, and $O(p,q)$, a pseudovector (and more generally a pseudotensor) use the prefix pseudo in a different way, namely to denote an additional sign flip in the transformation law under an orientation reversing transformation.
III) On page 38 in chapter 2 of the book CFT by Di Francesco et al. is written:

[...], the Lorentz group is isomorphic to $SO(d-1,1)$, the group of pseudo-orthogonal rotations.[...]

One may draw two conclusions:


*

*Di Francesco et al. are not very careful in distinguishing between the Lorentz group $O(d-1,1)$ and the proper Lorentz group $SO(d-1,1)$. In fact, it is possible that they really mean the restricted Lorentz group $SO^+(d-1,1)$.

*A pseudo-rotation is for Di Francesco et al. a Lorentz transformation (modulo the ambiguity mentioned in point 1).
IV) Finally, let us mention that there exists an unrelated notion of pseudorotations in chemistry.
