Here are a couple of different knives that we use in Kerala. The one on top is the one I've seen and used for most of my life, whenever I actually find the need to use one of these, of course. Speaking of uses, I generally make use of this kind of knife to trim branches of some it-was-once-a-bush-but-now-it's-a-tree type plants, or to cut firewood down to size, or even to attack some unsuspecting coconut and break it open. In Malayalam this kind of knife is called a "kodu vaal".
The knife below, with the flat, widening blade is, as far as I'm concerned, called a "kaththi". The word means knife, in Malayalam, and I know that's a little too generic, but most of the people I asked seemed stumped when asked to provide a specific name. However, I really like the feel of this knife because it has a nice center of balance and is really sharp. The little hook on the end aids in the portability of this knife up a coconut palm. Why would anyone carry it up there? Because toddy tappers -- "toddy" is the local brand of naturally fermented alcohol derived from the coconut palm -- use this knife extensively in the lofty treetops.
I've included a foot-long ruler for your reference. And yes, it is upside down. :-|