That doesn't sound like "inverting". If that is what it means then it is indeed a bad name.
I always thought it means making one of the leaf nodes a root of the tree. Physically, it would look like taking one of the leaf nodes with your fingers and "hanging" the tree off of it.
Inverting means inverting the sort order. The easy answer is to encapsulate the tree in a new structure and add a Boolean flag called “inverted,” since you’re just reinterpreting the meaning of left and right children.
What you describe is called “rotation,” and is used to rebalance.
I always thought it means making one of the leaf nodes a root of the tree. Physically, it would look like taking one of the leaf nodes with your fingers and "hanging" the tree off of it.