Fake News may take many different forms, but the essential element is always that it is partially or completely false. It may be urban legend, rumor, badly sourced writing, deliberate misinformation, or intended as humor or parody. As an information consumer, it is your responsibility to evaluate news sources for credibility, authority, and purpose, both for your own information needs and to prevent you from accidently sharing fake news to others.
The expression "Alternative facts" garnered widespread media attention on January 22, 2017 when used by Kellyanne Conway, Counselor to President Trump, while on NBC's Meet the Press. This sparked a national conversation on whether facts are variable and subject to interpretation.
Oxford English Dictionary defines fact as:
"That which is known (or firmly believed) to be real or true; what has actually happened or is the case; truth attested by direct observation or authentic testimony; reality."
Source: The International Federation of Library Associations and Institutions (IFLA)