Both are worn to cover up legs and its starts from waist to feet, so what are the difference?
we are going to make thing short and simple so we will not confuse you even further.
Pantyhose are usually on the lower denier (which is a measurement for fabric thickness, lower number = thinner fabric = sheer or see through. Higher number = thicker fabric = opaque) worn to hide visible veins, blemishes or scars on your legs, because pantyhose are thinner it can be worn during fall/summer season.
Tights on the other hand is thicker, that is suitable to be worn during winter season. Both tights and pantyhose are similar in terms of coverage which is from waist to toes but pantyhose tends to be thinner or sheerer, and tights are thicker or opaque.