A relational table stores a collection of related -

Answer 1

Related data

Answer 2

For example. If you need to store user information, you would need usernames and passwords. If you need to store other information about the users like their emails and addresses, you'd store usernames, passwords, emails, and addresses in one table. Then their specific account details can be in another table.
These would be columns in one table:
username
password
email
address