Discover means to find something (or figure out how something works) before everyone else does.
American children are taught that Christopher Columbus “discovered” America. This piece of historical trivia often prompts a subset of American children to narrow their eyebrows and say, “Wait a minute. Weren’t there people here already? Didn’t they discover America? And wasn’t it not even called America until 1507?”
Columbus did not “discover” America. Of course he didn’t.
But the word has stuck because it makes the story more exciting. You imagine a great explorer, all alone (he wasn’t alone), setting out to conquer the vast ocean in a tiny sailboat (actually it was a caravan of three ships) even though everyone thought he would fall off the edge of the earth (no, eveyone did not think that) — a lone genius dragging the rest of humanity into the future.
Real discoveries rarely work out this way.