Translation guide
The folded flaps of cloth on the front of a jacket or coat, especially the part that is folded back on each side of the chest.
Referring to the folded front part of a jacket or coat
General word for collar or lapel. Context usually makes it clear you mean the lapel of a jacket.
彼はジャケットの襟を直した。
He adjusted the lapel of his jacket.
Loanword from English, specifically means 'lapel'. Common in fashion contexts.
このジャケットはラペルが細い。
This jacket has narrow lapels.
Literally 'lower collar', sometimes used for the lapel part that folds back. Less common.
スーツの下襟にピンをつける。
Attach a pin to the suit's lapel.