Translation guide
A round collar is a neckline style that forms a circle around the neck, common on T-shirts, sweaters, and casual wear. In Japanese, it is usually described as 丸首 (marukubi) or 丸襟 (marueri), with specific terms for crew necks and other variations.
round collar
Most common term for T-shirts and casual wear.
Describing a garment with a simple round neckline, like a T-shirt or sweater.
The most common term for a round neckline, especially on T-shirts, undershirts, and casual tops. Literally 'round neck'.
This T-shirt has a round collar.
I'm looking for a round-neck sweater.
Literally 'round collar', used for shirts, blouses, and more tailored garments. Slightly more formal than 丸首.
I like round-collar blouses.
Loanword from English 'crew neck', commonly used for T-shirts and sweaters with a round, close-fitting neckline.
I bought a crew-neck knit.
Distinguishing a round collar from V-necks, turtlenecks, etc.
Use this phrase to specify you want a round neck, not a V-neck.
I'd like the round-neck one, not the V-neck.
Another loanword, less common than クルーネック, sometimes used in fashion contexts for a wider, more open round neckline.
This round-neck cut-and-sew is easy to wear.
丸首 (marukubi) is the most general and common term for a round neckline, especially on casual garments like T-shirts. 丸襟 (marueri) is used for shirts and blouses with a collar, implying a more tailored look. クルーネック (crew neck) is a specific style of round neckline that fits closely around the neck, often used for sweaters and T-shirts.