https://docs.temporal.io/docs/concepts

Namespace

Temporal guarantees a unique Workflow Id within a Namespace

An Activity Definition is the code that defines the constraints of an Activity Task Execution.


Activity Id
A unique Id that identifies an Activity Execution

A Task Token is a unique Id that correlates to an Activity Execution.

Activity Execution completion calls take either a single Task Token, or the Namespace, Workflow Id, and Activity Id as a set of arguments


Task
A Task is the context that a Worker needs to progress with a specific Workflow Execution or Activity Execution.

two types of Tasks
Activity Task
Workflow Task


Task Queue

Workers poll for Tasks in Task Queues via synchronous RPC.
Task Queues enable load balancing across a large number of Worker Processes

Task Routing
routing of specific Tasks to specific Worker Processes or even a specific process.

Task Token




Workflow Execution
A Workflow Execution is either Running or Closed
closed ( Completed , Continued As New, Failed, TimedOut, Cancelled,  Terminated )


A Workflow Execution is uniquely identified by its Namespace, Workflow Id, and Run Id.

A Run Id is a globally unique, platform-level identifier for a Workflow Execution.

A Workflow Id is a customizable, application-level identifier for a Workflow Execution that is unique to an Open Workflow Execution within a Namespace.


Event
https://github.com/temporalio/api/blob/master/temporal/api/enums/v1/event_type.proto

Event History

A Temporal Cluster is the Temporal Server paired with persistence.


The Temporal Server consists of four independently scalable services:

Frontend gateway: for rate limiting, routing, authorizing
History subsystem: maintains data (mutable state, queues, and timers)
Matching subsystem: hosts Task Queues for dispatching
Worker service: for internal background workflows

Worker
Worker Entity  
A Worker Entity is the individual Worker within a Worker Process that listens to a specific Task Queue.

A Worker Process is responsible for polling a Task Queue, dequeueing a Task, 
executing your code in response to a Task, and responding to the Temporal Cluster with the results.

A Worker Program is the static code that defines the constraints of the Worker Process