Throughout the OpenMRS API and data model, you will notice references to the terms retire, delete, and remove. Here are some definitions to help you understand why and where these terms are used in relation to concepts.
Concept managers can retire unused concept or concepts which are no longer needed. In the database, a retired concept will be marked as 1 to indicate it's retired. Retired concepts will not show up under the Concept Dictionary search user-interface, unless the "include retired" tick box is selected when searching for a concept. Data that references retired metadata remains valid. It is possible to "un-retire" a retired concept.
Once a concept is deleted from the Concept Dictionary, that concept will be removed from the concept table in the database. The concept will also not be visible in the Concept Dictionary page of the user interface. It will not be possible to retrieve it unless users retrieve it under previous archives. A concept cannot be deleted if any observations have been stored with it.
Removed Concept Names
When editing a concept in the user-interface, you have the option to "remove" a concept name. This functionally deletes the data (from a user's perspective) without actually deleting it at the database level. The data remains in the concept_name table, but is marked as voided and no longer appears in the UI.