Re: What was the Greeks basic idea of 'atomos'?

The Greek word tomos (tomos) means "cut" and is the root of words like anatomy ("cut up" - dissect), microtome ("tiny cut" - a tool used to make tissue sections for microscopy), and of course tome (originally a single volume of a larger work; i.e. a cut of a larger book). The Greek prefix a- is negative, so atomos translates as "no cut". An atom is, therefore, something that cannot be cut, or said another way, atomos means "indivisible" - since everything we can see can be divided and since division results in smaller pieces, to have a smallest bit of something, this bit must be indivisible, or there would be something smaller. Thus the original atomic theory was simply that there was a limit to how small matter could be, and these smallest bits of matter were, therefore, indivisible or "atomic". Originally, this was taken to mean that atoms were irreducible and indestructible. Some of this sense is still used in the modern definition of the atom as "the smallest unit of an element, having all the characteristics of that element" [American Heritage Dictionary]. Similarly, a molecule is "the smallest unit of a compound, having all the characteristics of that compound" [American Heritage Dictionary], and likewise breaking the bonds of the molecule or splitting the atom changes its characteristics such that it is no longer the same compound or element. While atoms are no longer considered indestructible, they are still irreducible from the perspective of chemistry.