"Turtlenecked" refers to a style of sweater or top that has a high collar that can be folded over and covers the neckline. Synonyms for this term include "polo necked", "roll-necked", "mock-necked", and "high-necked". A "polo necked" top is similar to a turtleneck, but the collar is shorter and doesn't fold over. A "roll-necked" top has a loose, rollable collar that can be worn up or down, while a "mock-necked" top has a shorter collar that sits higher on the neckline. A "high-necked" top simply refers to any garment with a high collar, without specifying the style or shape of the collar.