from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having the form of anything that serves to shade, such as a treetop or especially an umbrella.
from the GNU version of the Collaborative International Dictionary of English
- adj. Having the form of anything that serves to shade, as a tree top, an umbrella, and the like; specifically (Bot.), having the form of an umbrella; umbrella-shaped.
from The Century Dictionary and Cyclopedia
- Having the general form of an umbrella, as a mushroom. See cut under Agaricus.
Latin umbraculum anything that furnishes shade, a bower, umbrella (diminutive of umbra a shade) + -form. (Wiktionary)