Reading is one of her favourite hobbies because it allows her to explore different worlds.
Here the word 'Reading' is a/an -

• Reading is one of her favourite hobbies because it allows her to explore different worlds.
- Here the word 'Reading' is a - Gerund.

Gerund:
- কোন বাক্যে Verb এর সাথে ing যোগ হয়ে যদি noun এর কাজ করে অর্থাৎ Verb ও noun এর কাজ করে, তাহলে তাকে Gerund বলে।
- সংক্ষেপে: Gerund = Verb + ing = noun = Verb + noun।
- Preposition এর object হিসেবে Verb+ing বসলে তা Gerund হয়।
- Gerund দ্বারা স্থির অবস্থা বা কাজ বোঝায়।

যেমন:
- Swimming is a good exercise.
- Reading books is my hobby.
- Reading is an excellent habit.
- Running every morning helps him clear his mind before work.
- Cooking together with friends can be a fun and relaxing way to spend an evening.
- I like dancing.