Final answer:
In a Big SQL database, the boolean data type is defined as BOOLEAN, which is used to store true or false values.
Step-by-step explanation:
In a Big SQL database, the data type defined for a boolean is BOOLEAN. This data type is used to store true or false values. When defining a column in a Big SQL table that needs to store boolean values, you would typically use the BOOLEAN data type. This is a standard practice across many SQL-based databases, providing a straightforward way to handle true/false data. It is important to use the correct data type to ensure the integrity and accuracy of the database.