Definition:Atom (Logic)

Definition
In a particular branch of logic, certain concepts are at such a basic level of simplicity they can not be broken down into anything simpler.

Those concepts are called atoms or described as atomic.

Different branches of logic admit different atoms.

Propositional Logic
In propositional logic, the atoms are statements.

Also defined as
Some sources define atom to mean what is defined in as a literal: a statement variable or the negation of a statement variable.

Linguistic Note
The word atom comes from the Greek $\alpha \tau o \mu o \sigma$ for unbreakable or indecomposable.