A central part or core of an object, often referring to a cell or atom.

In a more abstract sense, the central or most important part of something.

किसी चीज़ का केंद्रीय या सबसे महत्वपूर्ण हिस्सा।

English Usage: The nucleus of the proposal is its focus on sustainability.

Hindi Usage: प्रस्ताव का नाभिक स्थिरता पर ध्यान केंद्रित करता है।