Kaa, pronounced Kar, is the snake's name in "The Jungle Book." He is a python. Kipling based this name on the hissing sound snakes make with an open mouth.
Kaa's name is not the only one with an unexpected pronunciation; the Mow in Mowgli rhymes with cow. While Kipling made up Kaa and Mowgli, he took other names from Hindustani origins. Baloo, pronounced Bar-loo, is Hindustani for bear, and Bagheera, pronounced Bug-eer-a, is Hindustani for panther or leopard.
Kaa, Mowgli, Baloo and Bagheera all appear in both Kipling's books and Disney's animated film, though their personalities differ between the two.