Factoid is both - Truth & Not-a-truth. But in todays world it usually (actually overwhelmingly) means an interesting piece of trivia.
From Wikipedia:
[Factoid] The term was coined originally in 1973 to mean a "piece of information that becomes accepted as a fact even though it’s not actually true, or an invented fact believed to be true because it appears in print." Since then, the term has evolved from its original meaning, in common usage, and has assumed other meanings, particularly being used to describe a brief or trivial item of news or information.
From Wikipedia: [Factoid] The term was coined originally in 1973 to mean a "piece of information that becomes accepted as a fact even though it’s not actually true, or an invented fact believed to be true because it appears in print." Since then, the term has evolved from its original meaning, in common usage, and has assumed other meanings, particularly being used to describe a brief or trivial item of news or information.