The word student doesn't stand for an acronym, it's a noun that refers to a person who is enrolled in an educational institution (such as a school, college, university, etc.) and is at the moment engaged in learning and studying various subjects or disciplines.
Students typically attend classes, complete assignments, and take exams as part of their educational pursuits.
The word student isn't an abbreviation or acronym, but rather a common English word used to describe individuals who are learning and gaining knowledge through formal education.