height of the neck; neckline height
Refers to the vertical dimension of a garment's neck or collar area, often in tailoring or clothing descriptions.
The neck of this shirt is too high, and it feels tight around my neck.
Could you adjust the suit's collar height a little lower?
Compound of 襟 (eri, 'collar') and 腰 (koshi, 'waist' or 'height'), referring to the 'waist' or height of the collar. The exact historical derivation is uncertain, but the term is used in tailoring contexts.