The term "screwtop" is often used to refer to a type of bottle or jar cap that twists on and off using a threading mechanism. However, there are a variety of synonyms for this word that can be used to describe the same type of cap. Some of these include screw cap, twist cap, threaded cap, and screw-on lid. Other similar terms might include screw closure, twist-off cap, or even simply a screw bottle top. No matter what you call it, the basic idea is the same - a cap that can be easily removed and resealed using a simple twisting motion.