Bleachers are probably best described as fixed benches in a tiered grandstand – the type you might find at a football (soccer) ground in most European countries. They tend to be uncovered, and it's thought that the name bleachers might have originated from the fact that they were bleached by being exposed to sunlight.

What is the definition of fixed seating?

Fixed seating is just what it sounds like, consisting of chairs which are not portable or stackable, but which are secured to the floor in some fashion, such as by bolts.

What is bleacher seating?

Bleachers (North American English), or stands, are raised, tiered rows of benches found at sports fields and other spectator events. Stairways provide access to the horizontal rows of seats, often with every other step gaining access to a row of benches.