| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 3,919,113,411 visitors served. |
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
umbra |
Also found in: Dictionary/thesaurus, Acronyms, Encyclopedia, Wikipedia | 0.01 sec. |
|
|
umbra [um´brah]
the part of a shadow in which there is no light from any light source. a sharp appearance to the edges of a structure on a radiograph.
penumbra 1. Region of very low illumination on a dark background. 2. Zone in which the brightness varies from some illumination to zero (umbra) in the shadow cast by an opaque object intercepting light from an extensive light source. See shadow. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
|
| Medical Dictionary |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup |
|---|