atom

The smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons.

Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis: the ability to convert water and carbon dioxide into carbohydrates and waste oxygen using solar energy. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the water-oxidizing complex, made up of manganese atoms and a calcium atom.

A hypothetical particle posited by Greek philosophers as an ultimate and indivisible component of matter.

The smallest, indivisible constituent part or unit of something.

Towards the following morning, the thermometer fell to 5°; and at daylight, there was not an atom of water to be seen in any direction.

But at this critical moment the pirate astern sent a mischievous shot and knocked one of the men to atoms at the helm.

In logical atomism, a fundamental fact that cannot be further broken down.

The smallest medieval unit of time, equal to fifteen ninety-fourths of a second.

A Meitei surname from Manipuri