A lookup field retrieves the value(s) of a specific field from a linked record or multiple linked records. This functionality lets you bring information from one table into another seamlessly.
When you create a lookup field, you specify which linked field it refers to, and then which field in those linked records to display. The lookup field automatically shows the data from the connected records without duplicating or storing the information separately.
"A lookup field returns the value(s) for a specific field from a linked record (or records). You can use this to bring information from one table into another."
Author's summary: Lookup fields provide dynamic, linked data display between tables in Airtable, simplifying data aggregation and referencing without data duplication.