Commonly used acronyms:
* International Standard Number: Used to identify a standard.
* International Standard Name: Used to identify a specific name or term.
* Information Sharing Network: Used to describe a network that shares information.
* Integrated Systems Network: Used to describe a network of integrated systems.
* Internet Service Network: Used to describe a network that provides internet services.
* Inventory Serial Number: Used to identify a specific item in inventory.
Less common acronyms:
* ISN Group (India): A company that provides IT services.
* Independent Security Network: A network of independent security professionals.
* International Security Network: A network that deals with international security issues.
Other possibilities:
* It could also be an abbreviation for a person's name.
* It could stand for a specific term used in a particular industry or field.
To determine the correct meaning of "ISN," you'll need more context. For example, what is the subject of the conversation or document where you encountered this abbreviation?