Turtle-necks are a type of neckline that covers the neck with a close-fitting, folded collar. There are several synonyms for the word "turtle-neck" such as polo-neck, roll-collar, mock-neck, and funnel-neck. A polo-neck is similar to a turtle-neck but has a knitted collar that can be turned down, whereas a roll-collar can be rolled up to provide extra warmth. A mock-neck is a collar that resembles a turtle-neck but is shorter in length, and a funnel-neck is a wider version of the turtle-neck collar. All of these synonyms offer different variations on the classic turtle-neck design, giving fashion enthusiasts a wider range of options to choose from.