A mathematical expression that describes a collection of objects.

A fixed or established group or collection.

एक निश्चित या स्थापित समूह या संग्रह।

English Usage: She has a set expression that reveals nothing.

Hindi Usage: उसकी एक निश्चित अभिव्यक्ति है जो कुछ भी नहीं दिखाती।