change casing

Author: tfitzmac

articles/azure-resource-manager/management/overview.md

@@ -34,7 +34,7 @@ If you're new to Azure Resource Manager, there are some terms you might not be f
 * **declarative syntax** - Syntax that lets you state "Here's what I intend to create" without having to write the sequence of programming commands to create it. ARM templates and Bicep files are examples of declarative syntax. In those files, you define the properties for the infrastructure to deploy to Azure.
 * **ARM template** - A JavaScript Object Notation (JSON) file that defines one or more resources to deploy to a resource group, subscription, management group, or tenant. The template can be used to deploy the resources consistently and repeatedly. See [Template deployment overview](../templates/overview.md).
 * **Bicep file** - A file for declaratively deploying Azure resources. Bicep is a language that's been designed to provide the best authoring experience for infrastructure as code solutions in Azure. See [Bicep overview](../bicep/overview.md).
-* **Extension resource** - A resource that adds to another resource's capabilities. For example, a role assignment is an extension resource. You apply a role assignment to any other resource to specify access. See [Extension resources](./extension-resource-types.md).
+* **extension resource** - A resource that adds to another resource's capabilities. For example, a role assignment is an extension resource. You apply a role assignment to any other resource to specify access. See [Extension resources](./extension-resource-types.md).
 
 For more definitions of Azure terminology, see [Azure fundamental concepts](/azure/cloud-adoption-framework/ready/considerations/fundamental-concepts).