What do you call the two groove settings in a stapler?
Stapler anvils have two kind of grooves on the anvil that allow pins to close inwards and outwards?
What word/phrase is used to refer to these settings?
The two types are called stapling and pinning.
The pinning groove, also known as the sheer setting is used for papers/items that need to be fastened together temporarily, hence the outward bending of the staple. This method makes removal much easier than the normal stapling method, also known as the reflexive setting, which bends the staple inwards, causing a more permanent and harder to remove fastening.
(Wiki & Wiki)