Key rotation is the replacement of a cryptographic key with a new one, either on a fixed schedule or when compromise is suspected, and it is covered in full under cryptographic key rotation. "Key rotation" is simply the shorter, everyday form of the name used by engineers, security teams and cloud providers.
In payments, rotation applies to the keys that encrypt PINs and card data, sign messages between banks and protect application programming interface credentials. Payment terminals using per-transaction key schemes effectively rotate keys with every purchase, while keys held in hardware security modules are changed according to the organisation's cryptoperiod policy. Developers also use the term for replacing API keys and secrets, such as a merchant's credentials with a payment gateway.
In crypto, rotating a wallet key usually means moving funds to a new address controlled by a new key, because the old key cannot be changed once it controls an address. Rotation is one stage of the wider key management lifecycle.