# Terminology

You may want to familiarize yourself with a few terms before you start reading the documentation.

• Analyst: Anyone who performs an analysis. This is more general than referring to a data scientist.
• Ping: A message that is sent to Mozilla's telemetry servers. Generally speaking, a ping is received from Firefox and includes information about the browser state, user actions, etc. (more details). However, a ping can also be received from other Mozilla products or services
• Dataset: A set of data that include ping data, derived datasets, etc. It can also refer to a BigQuery dataset, which is a container for tables.
• Derived Dataset: A processed dataset, such as the clients_daily dataset. This is in contrast to a raw dataset, which is typically a collection of pings.
• Metric: Any quantity that we can calculate using our data and that, to some degree, measures some quantity of interest. See also standard metrics.
• Session: The time period that commences when a Firefox browser starts until the browser shuts down.
• Subsession: Sessions are split into subsessions when a 24-hour threshold is exceeded or an environment change occurs. (more details)