Institutional discrimination is when a group of people or an organization, like a school or a government, treats certain groups of people unfairly. This can happen because of their race, gender, religion, or other characteristics.
Imagine a playground where the big kids get to use all the toys, and the little kids only get to use one broken toy. This is kind of like institutional discrimination, because the big kids have more power to determine who gets what, and they are not treating the little kids fairly.
Sometimes, even if one individual in the organization is not personally racist or sexist, the policies and rules they make can still discriminate against certain groups. For example, if a boss only hires people who went to certain schools, but those schools are mostly attended by wealthy white people, they are still discriminating against people who cannot afford to go to those schools or are not white.
It is important to recognize and fight against institutional discrimination, so that everyone can have a fair chance to succeed no matter who they are or where they come from.