The curriculum is broken up into "departments" (subjects) and the "products" (students) move from station to station to undergo elements of the production process.
At each stage, "highly-skilled artisans" (teachers) provide input, make adjustments and assess for compliance against quality standards.
This process is scheduled according to a well-organised, structured and controlled timetable. If some part of the process is missed or omitted, this will need to be made up later, usually at the end of the day, or when the production line has shut down for the week.
"Products" (students) are arranged according to their date of manufacture (class, year level) and are kept together in groups associated with this date and "model class" (house groups, streams, forms). They often wear a badge and are clothed in a house style, so that they can be seen to belong to the same "brand."
Is it any wonder that the name we use in English for a bunch of fish who all appear the same and are all swimming in the same direction, is the same word we use for an educational institution?