Complex sentence: In American English, the term "tights" refers to pantyhose made from thicker material, or alternatively to opaque legwear typically made of a stretchy material such as spandex.
Split into simpler sentences: In American English, the term "tights" typically refers to pantyhose made from thicker material. In colloquial use, it can also refer to opaque legwear typically made of a stretchy material such as spandex.