In reference to anatomy, the second smallest level of organizational classification used when studying the structure of a living organism.

The organelle level deals with the function and structure of organelles and their relationship to the cells and body of the organism that they are a part of.

Due to the complexity of a living organism, it may be studied on one or more of several structural levels. These levels are as follows, starting from smallest (micro) to largest (macro).

1. Chemical Level
2. Organelle Level
3. Cellular Level
4. Tissue Level
5. Organ Level
6. Organ System Level
7. Organism Level