feat: Add more information around Entity Type

docs/110-key-terms-and-features/090-entity-type.md

@@ -1,23 +1,71 @@
 ---
 layout: cluedin
-title: Entity type
+title: Entity type (Business Domain)
 parent: Key terms and features
 nav_order: 9
 has_children: false
 permalink: /key-terms-and-features/entity-type
 tags: ["development","entities","entity-types"]
 ---
 
-An entity type indicates a specific business domain for data. It can represent physical objects, individuals, locations, and so on. An entity type should be global, timeless, and not bound to a specific data source (for example, Person, Organization, Car).
+An entity type represents a specific business domain for data. It can signify physical objects, individuals, locations, and more. Entity types should be **global**, **timeless**, and **independent of specific data sources** (e.g., Contact, Organization, Car).
 
-A golden record can have only one entity type. You can use built-in entity types or can create your own custom entity types.
+Each golden record is associated with exactly one entity type. You can leverage built-in entity types or define your own custom entity types.
 
-An entity type is assigned to a clue when the mapping is created. It is an important element of codes (entity origin code and entity codes).
+An entity type is assigned to a clue during the mapping process and plays a critical role in various codes, including entity origin codes and entity codes.
 
-**Entity type and codes**
+## Where Is Entity Type Used?
 
-An entity type is a foundational element used in the generation of codes. It always appears as the first part of any code.
+### Adding Semantic Context to Golden Records
 
-**Entity type format**
+The entity type provides **metadata**, such as a display name, icon, and descriptions, adding a semantic layer to golden records.
 
-An entity type always starts with a slash (/). CluedIn has a nested hierarchy of entity types that are separated by slashes. For example, “/Sales/Deal” indicates that the “Deal” entity type is a child of the “Sale” entity type.
+Golden records sharing the same entity type inherently share the same "semantic meaning."
+
+When defining entity types, it’s essential to balance specificity and genericness. Use terminology familiar to your line of business (LOB) to help identify records intuitively.
+
+{:.important}
+Tip: CluedIn is flexible—if you choose an initial entity type that needs adjustment, you can change it. However, changing entity types mid-project can be cumbersome, especially if deduplication projects, rules or streaming configurations have already been applied.
+
+### Filtering Golden Records
+
+Entity type acts as the default filter for many operations in CluedIn. Selecting the right entity type allows you to target groups of golden records that logically belong together.
+
+### Origin Entity Code (Primary Identifier)
+
+Entity type forms part of the primary identifier value. This structure enforces that records can only merge if they share the same entity type.
+
+## Entity Type Properties and Characteristics
+
+### Why Do I See a Slash (/) in Front of an Entity Type?
+
+Entity types have a unique code, represented as a simple string prefixed by a slash (/).
+
+The code uniquely identifies the entity type.
+
+Use concise, meaningful names for codes, avoiding non-alphanumeric characters where possible.
+
+### Nested Entity Types
+
+CluedIn supports nested entity types, allowing hierarchical organization of entity types. While not mandatory, this feature can help group entity types of the same nature.
+
+Example of Nested Entity Types
+```
+/Document
+/Document/XLS
+/Document/Video
+/Document/Audio
+```
+
+In this hierarchy, Video is a child of Document:
+
+#### Benefits of Nested Entity Types
+
+1. **Grouping Filters**: Nested entity types allow you to filter or stream entities collectively.
+For instance, using a filter such as starts with /Document would include all documents, regardless of their specific sub-entity type.
+
+2. **Streamline Reporting**: Nested types simplify reporting and analysis across related entity types.
+
+## Useful Resource for Entity Type
+
+- [Add or modify Entity Type](/management/entity-type)