What is the bias?

The term “bias” came up frequently in my lecture, and in retrospect, I am somewhat confused about how to explain bias when asked “What is bias?”

On the one hand, I learned that bias is the y-axis intercept, where in linear regression (y=mx+n), the n-term is the bias.

At the same time, the bias term is also used in relation to the bias-variance tradeoff, where bias is not the y-axis intercept but the systematic error of the model. Similarly, the term “bias” is also used in ethics when one says “the model is biased” because, for example, distorted training data would cause a model to evaluate people with a certain name.

Therefore, I would like to know whether this is basically all bias and the word has a different meaning depending on the context, or whether I have misunderstood something.