A lookup field is a type of field that creates a relationship between two objects and allows users to select a record from one object as a value for another object. A lookup relationship creates a one-to-many relationship between two objects, where each parent record can have many child records but each child record can have only one parent record. A lookup relationship also allows limited access to child records, meaning that users can see only those child records that they have access to based on their profile permissions and sharing settings. References: https://help.salesforce.com/s/articleView?id=sf.relationships_lookup.htm &type=5