2. something fictitious or unsubstantiated that is presented as fact, devised especially to gain publicity and accepted because of constant repetition.
To my mind, the connotation of factoid is that it's not false, but it's too simplified or stripped of context to be wholly accurate.
Consider, "Did you know that squids have eyes as big as bicycle tires?" That's not completely made up (squid do have the largest eyes of any animal) but to make it strictly accurate you'd need to change "squid" to "giant squid", "have" to "can have", and "bicycle tire" to "child's bicycle tire".
Ah, the second definition isn't one I've ever seen used? A factoid may be used inappropriately to support an unrelated argument, ("the last pirates were seen in the 1800s, right as climate change started") but they're still _true_.
That's actually the original meaning. "Factoids... that is, facts which have no existence before appearing in a magazine or newspaper, creations which are not so much lies as a product to manipulate emotion in the Silent Majority."
The meaning has since mutated, and of course there's no reason we should be constrained to the original.
It's the original and etymologically, it makes more sense, since "-oid" means "resembling." "Humanoids" are not human, for instance. But of course appeals to etymology are not a good way to determine what a word means.
Some dictionaries order senses by age and others by usage (which may be somehow measured or may just be up to the instincts of the editors), so this isn't a useful metric without knowing the standard of the dictionary we are talking about.
