Sanskrit is anbranch of Indo-European languages. It was first started in South Asia, and is the sacred language of Hinduism, the language of classical Hindu philosophy, and the language of Buddhist and Jainist historical texts.
Sanskrit is very important for many reasons:
The language of Nepal, Nepali, has many words derived from Sanskrit in it. This is because Nepali is also an Indo-Aryan language. Also, Hinduism was a huge religion in Nepal, and many, many Hindu religious texts are in Sanskrit.
Because of this, many names for things in Nepal are derived from Sanskrit. Take, for example, Annapurna I, the mountain. It is named after Annapurna, the Hindu goddess of food and nourishment. Its name in Nepali is अन्नपूर्ण, which is derived form Sanskrit. The anna part means 'food', and the purna part means 'food'. So, if you translate it, it means 'full of food', or 'everlasting food'.
This example is one of the many appearances of Sanskrit in Nepalese stuff. Keep that in mind that many of the Nepali names you see on this website are likely derived from Sanskrit.