As mentioned previously, there are two types of customizable entities in Dynamics CRM. They are Business entities and Custom entities. Business entities are customizable entities that are created by Microsoft and come as part of the default solution package. They are part of the three modules: Sales, Service, and Marketing. Custom entities are all the new entities that are being created as part of the customization and extending process.
Business entities are part of the default customization provided with the application by Microsoft. They are either grouped into one of the three modules of functionality, or spread across all three. Examples of Business entities include, but are not limited to: Account, Contact, Lead, Opportunity, Case, and so on.
Most of the properties of Business entities are customizable in Dynamics CRM. There are though certain items that are not customizable across these entities. These are in general the same type of...