Explain what multi-factor authentication (MFA) entails.

Multi-factor authentication (MFA) involves the use of more than one verification method to confirm a user's identity, significantly enhancing security. This typically combines two or more of the following factors: something the user knows (like a password), something the user has (such as a smartphone or a security token), and something the user is (biometric verification like fingerprints or facial recognition). By requiring multiple forms of identification, MFA reduces the likelihood of unauthorized access, as it is much harder for an attacker to possess all the required factors.

This approach is particularly crucial in the context of increasing cyber threats, as a single layer of security, such as just a password, can be easily compromised. Therefore, multi-factor authentication provides an additional layer of defense, making it a best practice in securing sensitive information and user accounts.