Here is a comment I posted in relation to an article :
If I had a "pair" of ears I could say that I'd heard your argument 4 times over. But I have a pair of ear. For the same reason that I wear a pair of trousers, I am to assume that a one-legged pair of pants is to be called a pant - which is something that I,as a male, would do if you told me that you were now going to remove your panties. Removing your pants is akin to removing your outer layer with your panties as the inner. But, if I said that I was now going to remove my pant, you may think I were an amputee. However, if I were to walk into the trees, I would be far busier than if I were to walk into the tree. By your logic, I would wear a "trouse" instead of a pair of "trousers" but I would then wear a pair of "trousers". Therefore my pant should be called a pair of "trouse's", that is the derivative of the plural. It would seem that the word, in it's spelling, is a connotation of the 'way' it is said rather than the 'way' it is spelled. (or should it be spealt?). Such is they beauty of the English language.