complete some definition

Author: thomas-tacquet

pages/serverless-containers/concepts.mdx

@@ -133,6 +133,8 @@ The Serverless infrastructure manages incoming request traffic. In scenarios lik
 
 ## Monitoring
 
+Monitoring is the process of continuously collecting and analyzing data about your Serverless applications and infrastructure to ensure they are healthy, performing well, and available.
+
 ### Logging
 
 Serverless Containers offers a built-in logging system based on Cockpit to track the activity of your resources. Refer to [monitoring Serverless Containers](/serverless-containers/how-to/monitor-container/) for more information.
@@ -242,6 +244,10 @@ A Serverless Container can have the following statuses:
 
 ## Triggers
 
+For Serverless Containers, a trigger is a setting that can start events that automatically interacts your service.
+
+A trigger could be an incoming scheduled HTTP request or a message being published to a queue. When the event occurs, the trigger invokes your service to run its code.
+
 ### CRON trigger
 
 A CRON trigger is a mechanism used to automatically invoke a Serverless Container at a specific time on a recurring schedule.
@@ -286,6 +292,8 @@ gRPC is supported on Serverless Containers, as long as you have enabled http2 (`
 
 ## Units
 
+Units are standardized measures of the computational resources, such as processing power and memory, allocated to run your service. The quantity of units you assign determines your application's performance capacity and directly influences its cost.
+
 ### vCPU
 
 vCPU is the abbreviation for **v**irtual **C**entralized **P**rocessing **U**nit. A vCPU represents a portion or share of the underlying physical CPU assigned to a particular container.