If pandas are from China and in Chinese they are called 熊猫 ("bear cat"), where did the word "panda," as seen in most western languages, come from?
I think this article answers your question..
Why is the panda called so?
The origin of the name panda is the Nepalese word 'nigalya ponya', which means 'eater of bamboo'. As used in the West, it was originally applied to the red panda, to which the giant panda was thought to be related.
Until its relation to the red panda was discovered in 1901, the giant panda was known as the mottled bear (Ailuropus melanoleucus) or partly-coloured bear. In Chinese, the giant panda is called the 'large bear cat'.
— Mayank Lavania, recd via e-mail
FYI, below is the red panda. I didn't know until now.
For people interested in the origin of 熊貓, check this blog entry.