# Terminology ## Cluster Terms | Phrase | Definition | | ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | agent | A process running in server or client mode. | | client/node | A Nomad client is responsible for running tasks assigned to it. A client registers itself with servers and watches for work to be assigned. When running the agent, the client may be referred to as a *node*. | | server | A Nomad server manages all jobs and clients, monitors tasks, and controls which tasks get placed on which nodes. | | dev_agent | The development agent is an agent configuration that provides useful defaults for running a single node cluster of nomad. | ## Work terms | Phrase | Definition | | ------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | task | The smallest unit of work in Nomad. Tasks are executed by task drivers like `docker` or `exec`, which allows Nomad to be flexible in the types of tasks it supports. Tasks specify their required task driver, configuration for the driver, constraints, and resources required. | | group | A series of tasks that run on the same Nomad client. | | job | The core unit of *control* for Nomad and defines the application and its configuration. It can contain one or many tasks | | job_specification/jobspec | A job specification, a |