Is it ethical (or legal, if applicable) to say you have a degree in X if your degree was in "X and Y" (single major)?
My degrees are mostly in the joint subject of Electrical Engineering and Computer Science. Past undergraduate, however, I pretty much exclusively studied in the computer science side of the department. Thus, I find it appropriate and accurate to describe myself either as having EECS degrees or CS degrees, but would not claim to have EE education past undergraduate. Likewise, my CS education included enough hardware and systems education that I am comfortable saying I received CE education. 

I think a similar analysis can be applied to any composite major. Most people and institutions understand that department names vary across institutions, so as long as you do not attempt to deceive about the skills you gave, it should be OK.