Polo-neck
Part of speech: noun
Definition: A high collar covering the neck; a turtleneck. A light type of shirt with such a collar.
Turtleneck
Part of speech: noun
Definition: A high, close-fitting collar, turned back on itself and covering all or most of the neck, on a sweater or similar garment.A turtleneck sweater.
Example sentence: I just bring a black turtleneck sweater everywhere - it's the greatest purchase of my life. Period.