a day or period of celebration

उत्सव

English Usage: Diwali is a big festival in India.

Hindi Usage: दीपावली भारत में एक बड़ा उत्सव है।

large in size or extent

बड़ा

English Usage: The elephant is a big animal.

Hindi Usage: हाथी एक बड़ा जानवर है।

a small number of

कुछ

English Usage: There were a few people at the concert.

Hindi Usage: कॉन्सर्ट में कुछ लोग थे।

the act of celebrating

उत्सव मनाना

English Usage: The birthday party was a big celebration.

Hindi Usage: जन्मदिन की पार्टी एक बड़ा उत्सव था।