Cloud (Defined)

1. a visible mass of particles of condensed vapor (as water or ice) suspended in the atmosphere of a planet (as the earth) or moon. 2. any similar mass, especially of smoke or dust.--By Leanne Burden Seidel
Clouds cover the sky as tourists walk down from the top of the Sydney Harbour Bridge on February 21. (Saeed Khan/AFP/Getty Images)
A blue sky and white clouds are reflected in a street mirror in Frankfurt, Germany, March 2. (Michael Probst/Associated Press)
A mushroom cloud in the sky after a car bomb exploded in eastern Mosul, during an ongoing military operation against Islamic State (IS) group militants. (DIMITAR DILKOFF/AFP/Getty Images)
Storm clouds frame the iconic landmark El Panecillo in the heart of downtown, in Quito, Ecuador, March 8. (Dolores Ochoa/Associated Press)
Colima volcano spews a cloud of ash near Carrizalillos, Mexico, Jan. 25. (Ulises Ruiz Basurto/EPA)
An Air Canada plane flies underneath dark clouds illuminated by some sun rays above Frankfurt, Germany, March 2. (Frank Rumpenhorst/dpa via AP)
Lightning flashes in storm clouds over the village of Dunlap, Ill., Feb. 28. A spring-like storm churning across the Midwest poses a risk of more bad weather for millions of people. (Ron Johnson/Journal Star via AP)
Dramatic clouds still lurk in Laguna Beach, Calif., after several days of powerful winter storms, Jan. 24. (Mindy SchauerThe Orange County Register via AP)
Clouds drift past the nocturnal skyline of Frankfurt am Main, western Germany, on Feb. 23. (FRANK RUMPENHORST/AFP/Getty Images)
Clouds of steam flows across the sky in the early morning from the Kendall Cogeneration Station in Cambridge. (David L. Ryan/Globe Staff)
An almost full moon is surrounded by clouds in Frankfurt, Germany, March 10. (Michael Probst/Associated Press)
A family hikes along Mule Deer Trail on a sunny afternoon in Thomas F. Riley Wilderness Park in Coto De Caza in San Juan Capistrano, Calif. (Mark Righmire/The Orange County Register via AP)
Smoke rises from a wildfire on March 19, in Boulder, Colo. (Seth Frankel/Associated Press)
Clouds are reflected in the glass facade of the Time Warner building in New York. (Mark Lennihan/Associated)
Light shines through fog and black clouds over the Swiss Alps. (FABRICE COFFRINI/AFP/Getty Images)
The sun rises over the clouds in front of the summit of Haleakala volcano in Haleakala National Park on Hawaii’s island of Maui, Jan. 22. (Caleb Jones/Associated Press)
Smoke billows from the Mt. Etna’s volcano, near Catania, in Sicily, southern Italy, March 16. (Salvatore Allegra/Associated Press)
A cloud in the sky over Palma Majorca, Spain, March 7. The Balearic Islands will experience springlike temperatures with clear skies during the next days. (Cati Cladera/EPA)
The Colima or Fuego volcano spews ash and smoke on Jan. 23, as seen from San Antonio, Colima State, Mexico. (HECTOR GUERRERO/AFP/Getty Images)
Two girls are silhouetted under low cloud while walking along a breakwater in Powell River, British Columbia, March 16. (Darryl Dyck/The Canadian Press via AP)
Low clouds blanket the horizon during a race inspection of a women’s downhill at the alpine ski World Championships, in St. Moritz, Switzerland, Feb. 9. (Alessandro Trovati/Associated Press)
Clouds pass over the Apostolic palace as Pope Francis delivers the Angelus prayer from his studio’s window overlooking St. Peter’s Square at the Vatican, March 5. (Gregorio Borgia/Associated Press)
One World Trade Center, top left, and other New York and New Jersey buildings are seen under low hanging clouds lit up with the rising sun, Jan. 5 in Jersey City, N.J. (Julio Cortez/Associated Press)
The Tornado steam locomotive pulls the first timetabled main line steam-hauled service for half a century across the Ribblehead viaduct in North Yorkshire. on February 14 in Appleby, England. (Christopher Furlong/Getty Images)
Rain clouds sit over McLean Park as rain delays the start of the 2nd one-day international cricket match between New Zealand and Australia at McLean Park in Napier on February 2. (MARTY MELVILLE/AFP/Getty Images)
Lightning bolts light up the sky near the world’s tallest building, the Burj Khalifa, in Dubai, United Arab Emirates, March 25. (Jon Gambrell/Associated Press)
Steam rises into the sky from the cooling tower of the German nuclear power plant ‘Isar’ (KKI) near Essenbach, southern Germany, March 16. (CHRISTIAN BRUNA/EPA)
A broad tornado capable of leaving “catastrophic” damage in its wake churned across the Oklahoma landscape. (Hayden Mahan via AP)
A nearly full moon is flanked by clouds as it rises near the Insurance Building in Olympia, Wash. (Ted S. Warren/Associated Press)
Boats sit docked in front of the MIT Sailing Pavilion as clouds hang over Boston. (Keith Bedford/Globe Staff)
Scattered clouds dot the sky at sunrise as surfers make their way to the water south of the Huntington Beach Pier, a day after storms pounded Orange County in Huntington Beach, Calif. (Mark Rightmire /The Orange County Register via AP)
Buildings are seen on a polluted day in Beijing. China’s capital city started the year under a heavy blanket of grey smog, with a concentration of toxic particles 20 times higher than the maximal level recommended by the World Health Organization, as a new pollution cloud was - again - striking the country. (GREG BAKER/AFP/Getty Images)
Clouds are mirrored in a floated meadow in Ruderatshofen, southern Germany, March 10. (Karl-Josef Hildenbrand/dpa via AP)
Tampa Bay Rays pitcher Chih-Wei Hu, of Taiwan, warms up as storm clouds pass after a rain shower at a spring training baseball workout in Port Charlotte, Fla. on Feb 22. (David Goldman/Associated Press)
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