Well segregation is segregation, with positive or negative overtones depending on the context like how we still to this day segregate restrooms by gender norms.

Affirmative action does not necessarily mean segregation either. The NFL's "Rooney Rule" requires a minority candidate to be interviewed for head coaching vacancies but doesn't require one be selected. We'd still call that affirmative action.

Rather it means merely that instead of just stopping the negative action applied against a minority and letting history take its course, that some positive action is taken to repair the damage done to the minority group, in order to actually have a chance at real equality in the future. This could include means such as segregated advocacy groups but encompasses much more.