ˌtop-ˈdown BrE AmE adjective [only before noun] British English
1 . a top-down way of organizing a business is one in which the most important people make decisions and tell the people below them what they should do:
The company has a top-down management system.
a top-down approach to decision-making
2 . a top-down way of understanding or explaining something starts with a general idea and adds details later