Translation guide
A detachable lock with a hinged or sliding shackle, used to secure gates, lockers, or chains.
The physical object: a portable lock with a shackle.
The standard word for 'padlock' in Japanese. Literally 'Nanjing lock', but used for any padlock.
I put a padlock on the locker.
This padlock can be locked without a key.
Loanword from English. Used in technical or product contexts, but less common in everyday speech.
This padlock is waterproof.
The act of securing something with a padlock.
In casual conversation, Japanese speakers might simply say 鍵 (かぎ) to refer to a padlock, especially if the context is clear. However, 鍵 primarily means 'key' or 'lock' in general, so 南京錠 is more precise.
I locked my bike with a padlock.