What is the meaning of Offensive_line?

The five players of the team possessing the ball comprising the center, the left and right offensive guards, and the left and right offensive tackles who are positioned around the ball at the line of scrimmage.

The seven players required to be within one yard of the line of scrimmage in an offensive formation.

All of the offensive players, whether obligatory or not, lined up one yard or less from the line of scrimmage.

Source: wiktionary.org