Translation guide
A small chain or ring for holding keys. In Japanese, the most common term is キーホルダー, but other words exist depending on the type.
The most common way to refer to a keychain, often with a charm or decoration.
The standard loanword for 'keychain' or 'key holder'. Used for both functional and decorative keychains.
This keychain is a souvenir from a friend.
Refers specifically to a key ring, the metal loop that holds keys. Less common for decorative items.
Put the key on the key ring.
A less common loanword, sometimes used for a chain-style keychain. キーホルダー is more natural.
That keychain has a long chain attached.
A plain metal ring for holding keys, without decoration.
A device or object for holding keys, often mounted on a wall.
For most situations, キーホルダー is the safest and most natural choice. It covers both decorative and functional keychains.
I found a cute keychain.
I bought a new keychain.
Attach the key to the key ring.