Most commonly, it means "swell" or "roll" in the context of the sea or ocean. It refers to the gentle, undulating movement of the water, typically caused by wind or distant storms.
Here are some other meanings of "houle":
* "Houle" can also refer to a "depression" or "hollow", especially in the context of terrain. For example, "une houle dans le terrain" means "a depression in the terrain."
* Figuratively, "houle" can mean a "surge" or "wave" of something intangible. For example, "une houle de colère" means "a surge of anger."
To determine the specific meaning of "houle" in a given situation, it's important to consider the context in which it's used.