4d51ede8_rks_Search_UI_2_9___Lucidworks__Description
[Parameter] Use for De-duplication [Fields API Attribute Name] use_for_deduplication [Description] 
This will use content indexed in this field for determining duplicated content and removing it from a user's result list.
Field Configuration - LucidWorks Search UI 2.9 - Lucidworks
Description