Some people still call this sand paper, as it appears, certainly at the courser grits, that there is sand on a paper backing.
People in the trade call these abrasives, as it pretty much says what it does on the tin.
It is common for people to not understand how abrasive grits are labelled.
The higher the number the finer the grit, and therefore the less abrasive it is. For example, a 60 grit is more abrasive than a 120 grit, and a 120 grit is a lot more abrasive than a 400 grit.
But why use different grits?