What is cloud?

  • (verb): Billow up in the form of a cloud.
    Example: "The smoke clouded above the houses"
    See also — Additional definitions below


In meteorology, a cloud is a visible mass of liquid droplets or frozen crystals made of water or various chemicals suspended in the atmosphere above the surface of a planetary body. These suspended particles are also known as aerosols. Clouds in earth's atmosphere are studied in the cloud physics branch of meteorology. Two processes, possibly acting together, can lead to air becoming saturated; cooling the air or adding water vapor to the air. In general, precipitation will fall to the surface; an exception is virga, which evaporates before reaching the surface.

Read more about Cloud.

Some articles on cloud:

Entrainment (meteorology)
... environmental air into a preexisting air current or cloud so that the environmental air becomes part of the current or cloud ... The entrainment coefficient in clouds is one of the most sensitive variables causing uncertainty in climate models ... that assumes that the timescale for the mixing within a cloud was large compared to the condensation timescale ...
Jeans Instability - Jeans Length
... length is the critical radius of a cloud (typically a cloud of interstellar dust) where thermal energy, which causes the cloud to expand, is counteracted by gravity, which causes the cloud to collapse ... Jeans Length is where is Boltzmann's constant, is the temperature of the cloud, is the radius of the cloud, is the mass per particle in the cloud, is the Gravitational Constant and ... the cloud's mass divided by the cloud's volume) ...
Cloud - Extraterrestrial
... Within our Solar System, any planet or moon with an atmosphere also has clouds ... Venus's thick clouds are composed of sulfur dioxide ... Mars has high, thin clouds of water ice ...
Preston Cloud - Professional Career
... Cloud's professional career alternated between the United States Geological Survey (where he was chief paleontologist from 1949-1959) and academia (Missouri School of Mines and Metallurgy ... While at UCSB he founded that institution's Preston Cloud Research Laboratory, originally dedicated to paleomicrobiology and to studies of the first lunar geological samples ... Cloud was a member of the National Academy of Sciences for thirty years, he was chairman of the Geology Section and occupied positions in its Council and Executive Committee ...
Cloud Nine
... Cloud nine or on cloud nine is an idiom referring to a state of elation or happiness ... It may also refer to ...

More definitions of "cloud":

  • (noun): Out of touch with reality.
    Example: "His head was in the clouds"
  • (verb): Make overcast or cloudy.
    Synonyms: overcast
  • (verb): Make milky or dull.
    Example: "The chemical clouded the liquid to which it was added"
  • (noun): Any collection of particles (e.g., smoke or dust) or gases that is visible.
  • (noun): Suspicion affecting your reputation.
    Example: "After that mistake he was under a cloud"
  • (noun): A visible mass of water or ice particles suspended at a considerable altitude.
  • (noun): A cause of worry or gloom or trouble.
    Example: "The only cloud on the horizon was the possibility of dissent by the French"
  • (verb): Colour with streaks or blotches of different shades.
    Synonyms: mottle, dapple
  • (noun): A group of many insects.
    Example: "A cloud of butterflies"
    Synonyms: swarm
  • (verb): Make gloomy or depressed.
    Example: "Their faces were clouded with sadness"

Famous quotes containing the word cloud:

    On a cloud I saw a child,
    And he laughing said to me,

    “Pipe a song about a Lamb”;
    So I piped with merry chear.
    “Piper pipe that song again”—
    So I piped, he wept to hear.

    “Drop thy pipe thy happy pipe
    Sing thy songs of happy chear”;
    So I sung the same again
    While he wept with joy to hear.
    William Blake (1757–1827)

    Not for no cold did freeze,
    Nor any cloud beguile
    Th’eternal flowering spring,
    Torquato Tasso (1544–1595)

    Perhaps I stand now on the eve of a new life, shall watch the sun rise and disappear behind a black cloud extending out into a grey sky cover. I shall not be deceived by its glory. If it is to be so, there is work and the influence that work brings, but not happiness. Am I strong enough to face that?
    Beatrice Potter Webb (1858–1943)