Churn refers to the loss of customers, users or subscribers: customers who discontinue their service with one provider and switch to another, or stop using the service altogether. It is generally expressed as a percentage of the total customer base over a given period (e.g. monthly or annually).

Churn can be categorized into:

Voluntary churn: the customer voluntarily stops subscribing.
Involuntary churn: the customer leaves involuntarily due to external circumstances or company actions.
Transactional churn: the customer stops using the service (e.g. stops recharging their account or using an application or OTT service).
Partial churn: the customer does not leave the company, but reduces the scope of his or her services (e.g. deletion of a TV option).
Natural churn due to circumstances beyond the operator's or the customer's control (death, moving to an area without coverage).
Technological churn occurs when technological innovations render existing services obsolete (customer migration to fiber-optic or 5G solutions).

Depending on the customer and the context, churn can be:

permanent: a customer leaves the company and cancels his subscription or stops using the service,
or temporary: a customer stops using the service, or reduces consumption over a variable period ranging from a few days to a few weeks, or even longer.

Splio CVM Glossary