What is the definition of bias? In U. S History?

Bias means a strong inclination of the mind or a preconceived opinion about something or someone. A bias may be favorable or unfavorable: bias in favor of or against an idea.

-www.dictionary.com

Basically, bias means having an unfair or unbalanced opinion. Since history is a subject where people express their opinions it means that we have to be very careful to watch out for bias.

-community.dur.ac.uk

Explanation:

US History taught in schools is most of the time very biased, in an attempt to build patriotism early  in a young individual's mind. They rarely disclose the negative impact the US has had on many other countries (and if they do, it's often sugar-coated), ultimately focusing on the problems with other nations. They build a false superiority to other countries.

“the iliad” (gr: “iliás”) is an epic poem by the ancient greek poet homer, which recounts some of the significant events of the final weeks of the trojan war and the greek siege of the city of troy (which was also known as ilion, ilios or ilium in ancient times).