ETN stands for exchange traded note. It is a type of exchange traded product (ETP), meaning it is traded on exchanges like exchange traded funds (ETFs) and exchange traded commodities (ETCs).
Unlike other ETPs, ETNs seek to track the performance of an index or product by using a debt security, such as a swap agreement.
Some ETNs are unsecured investments, and may also have limited oversight from regulators. This lack of protection means that ETNs can have a high level of risk for a retail investor.