- An organ is a part of the body of a living being (organism) fulfilling a specific function such as the stomach, the liver, the ear ...
Organelles "small organs" are organized parts contained in the cytoplasm of each eukaryotic cell. They have certain specialized roles to play, and they all depend on each other. The organelles act in the cell as the organs act in the body like the Golgi apparatus, the vacuoles, the plastids ... They are all components of the cell.
Examples:
* Organisms: mitochondria, nucleus, plates etc ... -> they are structures inside the cells
* Organs: the liver, the skin, the brain, etc. -> these are groups of specialized cells that, together, provide a function in the body