The number of attributes in a relation is known as –

In relational database theory, a relation is a table with rows and columns. Each column represents an attribute, which is a property or characteristic of the data. The number of attributes in a relation is a fundamental property that defines its structure. The term used to describe the number of attributes in a relation is known as the 'degree' of the relation. This is a standard concept in database design and is used to define the schema of a table. For example, if a relation has 5 columns, its degree is 5. This helps in understanding the structure and complexity of the data stored in the relation.