Found somewhere on the internet:
"Now many knitters will know the word clapotis as the name of a popular scarf/stole pattern, published at Knitty.com (I've knit one and am getting ready to cast on for my second). Designer Kate Gilbert cites French women and their penchant for wearing scarves nearly year-round as the inspiration for the pattern. She doesn't say how she came up with the name. I assumed it was French and to be honest I worried much more about how to pronounce it (so as not to sound like an idiot when in the company of other knitters) than about what it actually meant.
"Today my friend Melinda mentioned that she was familiar with the term clapotis from her time kayaking. To quote her, 'It is that chop of irregular water that you get when waves are coming in and mixing with waves that are created from water bouncing back after hitting a rock cliff. It makes for unpredictable and bouncy paddling.' Her comments so intrigued me (while simultaneously making me feel the slightest bit guilty about not being more curious about the genesis of the pattern name).
"I did a bit of digging on the internet and found out that clapotis means 'lapping of water' or 'standing waves' in French and that a French physicist named Joseph Valentin Boussinesq coined the term in 1877. The American Meteorological Society glossary, points out in part of its definition of clapotis that 'a standing wave is a periodic vertical motion of the sea surface that does not propagate horizontally. It can be thought of as being created by the superposition of two identical waves propagating in opposite directions' (AMS Glossary).
"The diagonal patterns created in the clapotis, through dropped stitches and patterning yarn, do seem like waves coming from opposite directions. Now I know where the pattern name came from."
The first image, above, of the clapotis we are all familiar with, is from my friend Heather's blog. Used with absolutely no advance permission at all, but let's just all agree it is beautiful and deserves to be displayed everywhere. I checked with her and she said it was okay to use her photo. Isn't it lovely? Don't you just want to run out and buy some Noro Silk Garden and cast on for one just like it?
The second image, also used with no permission at all, is from here. It was taken by Mark Pecot and is of Marius Asipauskas; the location is the Lake Erie coastline, Lakewood, Ohio. Many thanks to Mark for letting me use his amazing photo. (Unlike Heather's photo, his does not make me want to run out and buy a kayak and try this. I have used up eight of my nine lives in the past year; I need to make the one I have left last as long as possible. Hazardous hobbies are right out. I'll stick to my knitting...)