Added actor to the glossary

source/_data/glossary.yml

@@ -30,6 +30,11 @@
     Actions are used in several places in Home Assistant. As part of a script or
     automation, actions define what is going to happen once a trigger is
     activated. In scripts, an action is called *sequence*.
+- term: Actor
+  definition: |-
+    An entity that receives a control signal and performs an action in a system.
+  aliases:
+    - actors
 - term: Add-on
   definition: >-
     Add-ons are additional standalone third-party software packages that can be

source/getting-started/concepts-terminology.markdown

@@ -36,7 +36,7 @@ Devices and entities are used throughout Home Assistant. To name a few examples:
 
 ## Entities
 
-Entities are the basic building blocks to hold data in Home Assistant. An {% term entity %} represents a {% term sensor %}, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other {% term entities %}. An {% term entity %} is usually part of a {% term device %} or a {% term service %}. Entities have {% term states %}.
+Entities are the basic building blocks to hold data in Home Assistant. An {% term entity %} represents a {% term sensor %}, {% term actor %}, or function in Home Assistant. Entities are used to monitor physical properties or to control other {% term entities %}. An {% term entity %} is usually part of a {% term device %} or a {% term service %}. Entities have {% term states %}.
 
 <p class='img'><img src='/images/getting-started/entities.png' style='border: 0;box-shadow: none;' alt="Screenshot showing the Entities table">Screenshot of the Entities table. Each line represents an entity.</p>