There is a misconception that the word Babur means a Tiger. Babur's name has appeared as Baber and Babar. There is not the slightest doubt, however that the name is Babur (Bah-boor) which is ultimately derived from the Indo-European word for beaver. Although it has often been suggested that Babur means tiger, it has, in fact nothing to do with the Persian work babr, "tiger". Mirza Mohmd Haydar explains how Babur was given as a nickname to Zahir-ud-Din. "At that time the Chagatai were very rude and uncultured and not refined as they are now. Thus they found his given name Zahir-ud-Din difficult to pronounce, and for that reason gave him the nickname [Babur]"
Mohmd Haydar Dughlat (A History of the Moghuls of Central Asia)
Baburnama by Babur