It can be used as a crafting material, palm fronds, as well as Wood Sticks, can be used as fuel for Campfires. They can be placed in a campfire either while it is burning or after it has burned out.
Palm fronds are also used in a Water Still to produce drinkable water. While holding the frond, you look at the base of the still and left click to add. Each frond will produce one unit of water, which can be drunk directly from the still, or collected in a flask to be stored for later use while more fronds are used to produce more water.