Noun
rheid (plural rheids)
(zoology) Any member of the Rheidae; a rhea.
rheid (plural rheids)
English Wikipedia has an article on:rheidWikipedia
(geology) A substance whose temperature is below the melting point and whose deformation by viscous flow during the time of observation is at least three orders of magnitude (1,000 ×) greater than the elastic deformation under the given conditions.