Bias in AI refers to the problem of unfair and unequal treatment of certain groups or individuals in artificial intelligence algorithms, models, and systems. This can occur due to various reasons such as the data used for training the AI model, the design of the model, and the personal biases of the people who create the model.

For instance, if an AI system used for hiring candidates is trained on data with a history of gender bias, it might have a tendency to prefer male applicants over female applicants, even if the female applicants are just as capable or more so. Bias in AI can also have negative consequences in fields like healthcare, criminal justice, finance, and others.

It's crucial to tackle and reduce bias in AI to make sure these systems are fair and unbiased. This can be achieved by using diverse and inclusive data sets, consistently testing AI systems for bias, and having a wide range of people involved in the creation and implementation of AI systems.