“Cove lighting” is the architectural lighting term used for this sort lighting installation. You build coves out of gypsum or wood and then install LED tape lighting into a plastic or metal channel and bounce the light off the cove to create indirect lighting. You can use cove lighting to illuminate a ceiling, or accent a wall, which is called perimeter cove lighting.

There are a number of other types of indirect light fixtures (and direct/indirect fixtures, most commonly as suspended linear fixtures with LEDs on both the top and bottom of the fixture).

The first picture in the article linked below has an architectural elevation diagram (basically a side profile) of cove lighting: https://www.architectmagazine.com/technology/lighting/cove-l...