be+lowered
131permafrost — /perr meuh frawst , frost /, n. (in arctic or subarctic regions) perennially frozen subsoil. Also called pergelisol. [1943; PERMA(NENT) + FROST] * * * Perennially frozen earth, with a temperature below 32 °F (0 °C) continuously for two years or… …
132rare-earth element — /rair errth /, Chem. any of a group of closely related metallic elements, comprising the lanthanides, scandium, and yttrium, that are chemically similar by virtue of having the same number of valence electrons. Also called rare earth metal. [1955 …
