What is defined as a tiny individual cell of a bacterium?

A tiny individual cell of a bacterium is defined as a bacterial cell. Bacteria are single-celled organisms that belong to the prokaryotic domain, meaning they do not have a membrane-bound nucleus. Each bacterium is a complete organism in itself, capable of living independently and carrying out all necessary life processes.

In contrast, a prokaryotic cell refers to a broader category that includes all single-celled organisms without a nucleus, which means that while a bacterial cell fits within this definition, it is not specific enough to denote the specific structure and function of the cell itself.

Eukaryotic cells, on the other hand, are more complex and contain membrane-bound organelles, including a nucleus, and are characteristic of organisms such as plants, animals, fungi, and protists, making them fundamentally different from bacterial cells.

A viral particle is not a cell at all, as viruses are acellular entities that require a host cell to replicate and cannot carry out metabolic processes independently. Hence, the term "bacterial cell" accurately and specifically identifies a tiny individual bacterium.