When I first started programming, I didn't know which of the two symbols / or \ was "forward slash" or "back slash", so I got into the habit of calling them "uphill" and "downhill", respectively. I still tend to use those terms when I'm working with people who aren't computer savvy, and those terms tend to be a bit more intuitive and help avoid confusion.
How is this an improvement?
Maybe call them right-slash and left-slash, with the lean prefix implied? This would probably help our right to left language friends.