According to Merriam-Webster dictionary, the definition of the word "fact" is: a piece of information presented as having objective reality. A fact is a piece of information that is independently verifiable; if we both count the same pile of pennies, we should each have the same total. Facts are facts.
Are your sources credible and useful, or are they a bunch of . . .?!
The CRAAP Test is a list of questions that help you determine if the sources you found are accurate and reliable. Keep in mind that the following list is not static or complete. Different criteria will be more or less important depending on your situation or need. View or print this PDF.
Should you avoid Wikipedia? Hear what Stephen Colbert has to say.
Bias referes to a tendency to believe that some people, ideas, etc., are better than others, which usually results in treating some people unfairly. When evaluating sources, it is important to look for and recognize bias so as not to confuse a writer's opinion with facts. It is equally important to be aware of your own biases so that you don't discount credible sources just because they differ from your opinions.
Fallacies are arguments that comes to a conclusion without evidence to support them, and they come in many varieties.