Dinosaur was the first word whose history I discovered.
I was amazed, because I hadn't known that words had histories - I thought they just popped up by themselves, like mushrooms. Or zits.
As a great Flintstones fan, I was delighted to find out that the dino bit of the word means terrible (at least, it did in the dictionary I had as a child - my Collins dictionary says, rather unhelpfully, fearful, which I now realise is a contranym ).
And the saur bit means lizard.
As well as being an extinct reptile (if dinosaurs were reptiles, which they almost certainly weren't (and there's also an idea around that there are still loads and loads of dinosaurs about, which we now call birds, so dinosaurs aren't definitely extrinct, either)) a dinosaur is any really old-fashioned person who has stopped noticing that things are always changing.
So...what is this Twitter thing all about, then...?
Dinosaur: from the Greek deinos, fearful or terrible, and sauros, lizard.