It is commonly called alumina, and may also be called aloxide, aloxite, or alundum depending on particular forms or applications. It commonly occurs in its crystalline polymorphic phase Î±-Al 2 O 3, in which it composes the mineral corundum, varieties of which form the precious gemstones ruby and sapphire.
rain cloud. (meteorology). Any cloud from which rain falls; a popular term having no technical denotation. 1  Facebook. 2  Twitter.
a steady falling of water from the sky in significant quantity winced as he walked out into the wet without any protection Synonyms cloudburst, deluge, downfall, downpour, rainfall, rainstorm, storm, rainRelated Words precipitation, shower; thundershower, thunderstorm, weatherNear Antonyms drizzle, mist, mizzle, scud, spit, sprinkle.