so scientists have these things called papers, which are really technical documents where they publish their findings. papers are hosted and published by "journals" (e.g.
Nature,
Science). if you get a "journal paper" it means you managed to get your name listed as one of the authors on a paper in a journal.
it's considered pretty amazing for even a grad school applicant to have a journal paper (because it means you did actual work and actually made a contribution to the hallowed halls of science). so of course it's even more amazing if you're still in high school. and you should probably know papers are like the bread and butter of grad students/other people in academia. in high school your success is measured by grades; in grad school it's how many papers you have. your papers determine your reputation and papers and authorship are usually at the forefront of a grad student's mind...but i'm just ranting now.
obviously different journals have different levels of prestige (and your position in the author list matters a lot too, but only if you're first or last author), but that's a whole different story entirely. if you want to know more about academia you should really ask the people at phdcomics.com, they have forums there for grad students and they're all keenly aware of such issues.