- megalomaniacLv 79 years agoFavorite Answer
Particles that make up atoms or basically anything smaller than an atom.
At one time, scientists thought that atoms were the smallest unit of matter. And then they discovered that they were made up of even smaller 'neutrons', 'protons' and 'eclectrons'. Those are examples of subatomic particles. But there's more...
Then scientists figured out that neutrons and protons are made up of various kinds of 'quarks' and other even smaller particles. So far there are 12 known sub-sub-atomic particles but we don't know if that's it or if there are even tinier ones.
Just recently a new tiny particle was 'discovered' or at least found to be very likely to exist, likely enough to pronounce it so, the Higgs-Boson particle but that's a different kettle of fish.