In reference to anatomy, one of seven levels of organizational classification used when studying the structure of a living organism.

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