I'm pretty sure the "700x38c" issue is covered here in the archives - it was confusing to me when I got back into biking again a year ago. Can't find the link now, but I think the "c" from the 700c wheel gets transposed, so 700x38c means a 38 mm tire for a 700c tire, which then gets shortened to "38c" tire. So, the c refers to the wheel size, not the tire size, which is assumed to be mm. Makes as much sense as anything else in the confusing vocabulary of wheel and tire sizes.
And good luck to the OP with the new tires.
