Originally Posted by
Xaqaria
The atom is divisible, it can be broken down in to electrons, protons, and nuetrons. These things are also divisible, and can be broken down into quarks and leptons, and as far as we know these may be broken down further. The hypothesis was that such a point particle exists that cannot be broken down in to smaller parts. It was believed that the atom was such a particle, thus it was given the name. It has been proven that it is not such a particle. Now, this does not mean that such a particle does not exist, but we as humans have yet to find it. It is believed in super-string theory that the string is an indivisible particle but as of now this is simply an idea, as no string has ever been observed or otherwise detected.