Simplify the following text for a Grade 8 native English-speaking person.
Original: When attached to the word stress , it literally means `` good stress '' . The term eustress was first used by endocrinologist Hans Selye in 1975 , when he published a model dividing stress into two major categories : eustress and distress .
Simplified: Eustress is positive or good stress , opposite to distress .