Apologies to John McKenzie but in my experience when referring to guitar strings 'top' and 'bottom' are about pitch and not position. On a right handed guitar, played by a right handed player, the top string (the string with the highest pitch) is on the bottom and the bottom string (the one that sounds lowest) is on the top.

Of course some left handed players will take that guitar, turn it upside down and play it like that and then the top string will be on top.