Final answer:
A primary key uniquely identifies a record in a database structure.
Step-by-step explanation:
In a database structure, a record is uniquely identified by a field or a combination of fields called a primary key. The primary key serves as a unique identifier for each record in a table. It ensures that each record in the database has a unique identity and allows for efficient retrieval and manipulation of data.
For example, in a student database, the primary key could be a student ID number assigned to each student. This ID number would uniquely identify each student record in the database.