Final answer:
The set of institutions, interests, and ideas that define a political era is known as political culture, which includes the political ideology and shared values within a political group.
Step-by-step explanation:
The set of institutions, interests, and ideas that shape a political era is often referred to as the political culture. Political culture encompasses the shared attitudes, values, and goals within a political group. It develops organically as individuals with particular interests find one another and form communities around these interests, which can later evolve into social movements or formal interest groups. Over time, these groups establish formal institutions with set rules and practices. Political ideology is an integral part of this culture, providing a framework that influences individual and collective political ideas and behaviors.