1 [singular, uncountable]
the state of being very interested in something, so that you want to look at it, learn about it etc [↪ obsession]
Police knew of his fascination with guns.
The children watched in fascination.
2 [uncountable and countable]
something that interests you very much, or the quality of being very interesting
hold/have a fascination for somebody
India will always hold a great fascination for me.
The fascination lay in the mystery of what was inside the box.