Definition - What does Yamuna mean?
The Yamuna river is the longest tributary of the Ganges (or Ganga) river, which is considered sacred by Hindus who worship it as the goddess, Yamuna. The Yamuna river originates from the Yamunotri glacier in the lower Himalayas and merges with the Ganges at Kumbha Mela - famous Triveni Sangamam.
According to yogic texts, the pingala nadi, which is associated with solar energy, also symbolizes the Yamuna river.
Yogapedia explains Yamuna
The Yamuna travels across many states before it reaches the Ganges. Hindu mythology portrays Yamuna as the daughter of the sun god and sister of the god of death, Yama, giving the river the name Yami. It is believed that one is absolved of fear of death upon bathing in the waters of the Yamuna.
Yamuna is considered holier than the Ganges as it was on its shore that the Hindu god, Krishna, played and it was in its waters that he swam. Hence, it is believed that bathing in the river frees one of all sins and leads to liberation.
The Yamuna river is a cultural symbol of Hinduism. Yami is considered a representation of love. The Yamuna bears the qualities of Yami and bathing in its waters is believed to enhance the goodness of oneself.