SB 4.25.49
mukhya nama purastad dvas
tayapana-bahudanau
visayau yati pura-rad
rasajña-vipananvitah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The fifth gate situated on the eastern side was named Mukhya, or the chief. Through this gate, accompanied by his friends named Rasajña and Vipana, he used to visit two places named Bahudana and Apana.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The mouth is here described as the chief or the most important gate. The mouth is a very important entrance because one has two functions to conduct with the mouth. One function is eating, and the other is speaking. Our eating is done with the friend Rasajña, the tongue, which can taste so many different types of foods. The tongue is also used for speaking, and it can speak of either material sense enjoyment or Vedic knowledge. Of course, here material sense enjoyment is stressed. Therefore the word rasajña is used.