1. The number of atoms in a molecule of a substance.
Usage: chemistry
2. The property of a database transaction that ensures it is treated as a single, indivisible unit—either all operations complete successfully or none do.
Usage: computing; database systems

Examples

• The atomicity of oxygen is one, meaning a single oxygen atom exists in its elemental form.
• Nitrogen has an atomicity of two because it naturally occurs as N₂ molecules.
• In database design, atomicity ensures that a money transfer either completes fully or rolls back entirely.
• The atomicity principle prevents partial updates that could corrupt data.
• Chemists use atomicity to classify elements and compounds by their molecular structure.