To better understand the term 'rent', let us consider the writings of David Ricardo and Adam Smith.

There were three parties to production in the past:

1) land owner
2) capitalist
3) workers

Their incomes respectively are titled:

1) rents
2) profits
3) wages

Rents are the income of the class, land owners.

The land owner doesn't really contribute to the production process as much as the capitalist and even less still than the workers.
I would also argue that the capitalist doesn't contribute much to the production process either.