How to say keychain in Korean
Korean: 키링[ ki-ring ]

Meaning
키링 means a keychain, usually a small item you hang on your keys. In everyday Korean, people also use this word for cute charms on bags or pouches. You will often hear it when people talk about buying, collecting, or giving small accessories.
Example sentences
가방에 키링을 달았어요.
I put a keychain on my bag.
새 키링 하나 샀어.
I bought a new keychain.
친구가 키링을 하나 줬어.
My friend gave me a keychain.