A single-celled organism that lacks a membrane-bound nucleus and other membrane-bound organelles.

Here's why this definition is the most accurate and comprehensive:

* Single-celled: Prokaryotes are always unicellular, meaning they exist as individual cells.

* Lack of membrane-bound nucleus: The genetic material (DNA) in prokaryotes is not enclosed within a separate membrane-bound nucleus, unlike eukaryotic cells. Instead, it is located in a region called the nucleoid.

* Lack of membrane-bound organelles: Prokaryotes lack other internal membrane-bound organelles like mitochondria, Golgi apparatus, endoplasmic reticulum, etc. These structures are found in eukaryotes and are responsible for various cellular functions.

Important distinctions from eukaryotes:

* Prokaryotes are generally much smaller than eukaryotic cells.

* They have a simpler internal structure with fewer specialized compartments.

* Prokaryotes reproduce asexually, mainly through binary fission.

Examples of prokaryotes:

* Bacteria

* Archaea

Therefore, the definition above accurately captures the defining characteristics of prokaryotes and distinguishes them from eukaryotic cells.