| Term: | penumbra |
| Definition: |
The sunspot area that may surround the darker umbra or umbrae. In its mature form it consists of linear bright and dark elements radial from the sunspot umbra. |
| Term: | penumbra |
| Definition: |
The outer, lighter portion of a sunspot. This structure has a striated or filamented appearance |
| Term: | penumbra |
| Definition: |