The part of a garment around the neck — a collar, lapel, or neckband.
寒かったのでコートの襟を立てて歩いた。
It was cold, so I walked with my coat collar turned up.
シャツの襟が汚れているから洗っておいてください。
The shirt collar is dirty, so please wash it.
彼女はドレスの襟元に飾りを付けた。
She added an ornament to the neckline of her dress.
The nape or scruff of the neck (the area at the back of the neck).
美容師が襟のあたりを短く切ってくれた。
The hairdresser cut the area around my nape short for me.
子供は寒くて母親の襟に顔をうずめた。
The child was cold and buried his face in his mother's collar/nape area.
犬が私の襟を軽く噛んで遊んだ。
The dog playfully nipped at my scruff/collar.