Why is Rajya Sabha called a permanent house?

There are two houses in the Parliament, Upper house and the Lower House.

The Rajya Sabha (Council of States) is the Upper House of Parliament. The House has a maximum of 250 members, out of which 12 members are nominated by the President for their expertise in specific fields of art, literature, science, and social services.

Each member of the Rajaya Sabha serves for a term of six years. But one third of its members retire at the expiration of every two years. Hence, it is a permanent house, as it does not dissolve.