From Longman Dictionary of Contemporary Englishcloudcloud1 /klaʊd/ ●●● S3 W3 noun 1 
in the sky [countable, uncountable]DN a white or grey mass in the sky that forms from very small drops of waterheavy/thick/dense etc clouds Dark clouds floated across the moon. Heavy clouds had gathered over the summit of Mont Blanc.low/high cloud Visibility was bad due to low cloud. → storm cloud, thundercloud2 in the airAMOUNT [countable] a mass of dust, smoke etc in the air, or a large number of insects flying togethercloud of dust/smoke/gas etc A cloud of steam rose into the air. clouds of mosquitoes buzzing around us3 problemWORRIED [countable] something that makes you feel afraid, worried, unhappy etccloud of the cloud of economic recessioncloud on the horizon (=something that might spoil a happy situation) The only cloud on the horizon was her mother’s illness. Fears of renewed terrorist attacks cast a cloud over the event (=spoilt the happy situation). He returned to New York under a cloud of gloom and despair.4 → under a cloud (of suspicion)5 → be on cloud nine6 → every cloud has a silver lining7 → be/live in cloud-cuckoo-land8 → the cloud → have your head in the clouds at head1(24)COLLOCATIONSADJECTIVES/NOUN + cloud a black/grey cloudBlack clouds usually mean rain.a dark cloud (=a black or grey cloud)A dark cloud covered the sun.a white cloudThere was a bright blue sky with a few white clouds.heavy/thick cloud (also dense cloud formal)By midday, heavy clouds had spread across the sky.low/high cloudThe weather was overcast, with heavy low clouds.storm cloudsDark storm clouds were moving in from the Atlantic.rain cloudsThe sky had been full of rain clouds for days.phrasesa bank/mass of cloud (=a large block of cloud)A heavy bank of cloud was creeping across the sky.a layer of cloudThe moon was shining through a thin layer of cloud.wisps of cloud (=long thin pieces)The plane flew through occasional wisps of cloud.a band of cloud (=a long narrow area)Long narrow bands of cloud stretched across the valley.a blanket of cloud (=a thick layer)In the morning, a blanket of cloud still covered the country.a veil of cloud (=a thin layer)A thin veil of cloud hid the moon.verbsclouds gather/formThe sky had darkened and clouds had gathered.clouds cover somethingFor days thick cloud had covered the whole sky.clouds clear/lift (=disappear)At last the rain had stopped and the clouds had cleared.clouds part (=move away from each other)Suddenly the clouds that covered the moon parted.clouds move/rollA narrow band of cloud has been moving across the country.clouds drift/float (=move slowly)A few clouds drifted across the top of the mountains.clouds race/scud (=move quickly)A wind was blowing and soft clouds were scudding across the sky.clouds hangHeavy grey clouds hung low in the sky.cloud + NOUNcloud coverThe cloud cover should disappear by the afternoon.cloud formation (=the shape in which cloud forms)There are many different types of cloud formation. THESAURUScloud noun [countable, uncountable] a white or grey mass in the sky that forms from very small drops of waterThe storm was still a way off but black clouds were gathering.Thick cloud obscured the top of the hill.fog noun [countable, uncountable] very thick cloud near the ground which is difficult to see throughThe cars crashed into each other in thick fog.The fog had lifted (=disappeared)slightly.mist noun [countable, uncountable] light cloud near the ground that makes it difficult for you to see very far. Mist is usually not as thick as fog. You often get mist near areas of water or mountainsThe morning mist was lifting and the sun was coming up.A grey mist hung over the water.The hills were shrouded in mist (=surrounded by mist).haze noun [singular, uncountable] smoke, dust, or mist in the air which is difficult to see throughHe saw the horses coming towards him through a haze of dust.The road shimmered in the heat haze.A pale blue haze hung over the far-off mountains.smog noun [countable, uncountable] dirty air that looks like a mixture of smoke and fog, caused by smoke from cars and factories in citiesThe city is covered in smog for much of the year.A smog warning was issued for parts of Southern Oregon.thundercloud noun [countable] a large dark cloud that you see before or during a stormHe watched the thunderclouds roll across the valley.vapour trail British English, vapor trail American English noun [countable] the white line that is left in the sky by a planeHigh overhead, a jet left its vapour trail across the blue sky.
in the sky [countable, uncountable]DN a white or grey mass in the sky that forms from very small drops of waterheavy/thick/dense etc clouds Dark clouds floated across the moon. Heavy clouds had gathered over the summit of Mont Blanc.low/high cloud Visibility was bad due to low cloud. → storm cloud, thundercloud2 in the airAMOUNT [countable] a mass of dust, smoke etc in the air, or a large number of insects flying togethercloud of dust/smoke/gas etc A cloud of steam rose into the air. clouds of mosquitoes buzzing around us3 problemWORRIED [countable] something that makes you feel afraid, worried, unhappy etccloud of the cloud of economic recessioncloud on the horizon (=something that might spoil a happy situation) The only cloud on the horizon was her mother’s illness. Fears of renewed terrorist attacks cast a cloud over the event (=spoilt the happy situation). He returned to New York under a cloud of gloom and despair.4 → under a cloud (of suspicion)5 → be on cloud nine6 → every cloud has a silver lining7 → be/live in cloud-cuckoo-land8 → the cloud → have your head in the clouds at head1(24)COLLOCATIONSADJECTIVES/NOUN + cloud a black/grey cloudBlack clouds usually mean rain.a dark cloud (=a black or grey cloud)A dark cloud covered the sun.a white cloudThere was a bright blue sky with a few white clouds.heavy/thick cloud (also dense cloud formal)By midday, heavy clouds had spread across the sky.low/high cloudThe weather was overcast, with heavy low clouds.storm cloudsDark storm clouds were moving in from the Atlantic.rain cloudsThe sky had been full of rain clouds for days.phrasesa bank/mass of cloud (=a large block of cloud)A heavy bank of cloud was creeping across the sky.a layer of cloudThe moon was shining through a thin layer of cloud.wisps of cloud (=long thin pieces)The plane flew through occasional wisps of cloud.a band of cloud (=a long narrow area)Long narrow bands of cloud stretched across the valley.a blanket of cloud (=a thick layer)In the morning, a blanket of cloud still covered the country.a veil of cloud (=a thin layer)A thin veil of cloud hid the moon.verbsclouds gather/formThe sky had darkened and clouds had gathered.clouds cover somethingFor days thick cloud had covered the whole sky.clouds clear/lift (=disappear)At last the rain had stopped and the clouds had cleared.clouds part (=move away from each other)Suddenly the clouds that covered the moon parted.clouds move/rollA narrow band of cloud has been moving across the country.clouds drift/float (=move slowly)A few clouds drifted across the top of the mountains.clouds race/scud (=move quickly)A wind was blowing and soft clouds were scudding across the sky.clouds hangHeavy grey clouds hung low in the sky.cloud + NOUNcloud coverThe cloud cover should disappear by the afternoon.cloud formation (=the shape in which cloud forms)There are many different types of cloud formation. THESAURUScloud noun [countable, uncountable] a white or grey mass in the sky that forms from very small drops of waterThe storm was still a way off but black clouds were gathering.Thick cloud obscured the top of the hill.fog noun [countable, uncountable] very thick cloud near the ground which is difficult to see throughThe cars crashed into each other in thick fog.The fog had lifted (=disappeared)slightly.mist noun [countable, uncountable] light cloud near the ground that makes it difficult for you to see very far. Mist is usually not as thick as fog. You often get mist near areas of water or mountainsThe morning mist was lifting and the sun was coming up.A grey mist hung over the water.The hills were shrouded in mist (=surrounded by mist).haze noun [singular, uncountable] smoke, dust, or mist in the air which is difficult to see throughHe saw the horses coming towards him through a haze of dust.The road shimmered in the heat haze.A pale blue haze hung over the far-off mountains.smog noun [countable, uncountable] dirty air that looks like a mixture of smoke and fog, caused by smoke from cars and factories in citiesThe city is covered in smog for much of the year.A smog warning was issued for parts of Southern Oregon.thundercloud noun [countable] a large dark cloud that you see before or during a stormHe watched the thunderclouds roll across the valley.vapour trail British English, vapor trail American English noun [countable] the white line that is left in the sky by a planeHigh overhead, a jet left its vapour trail across the blue sky. Examples from the Corpus
cloud• a cloud of flies• Dark clouds gathered overhead.• Dense cloud prevented the rescue helicopter from taking off.• Under dark, heavy clouds, I returned to the den on the river.• If clouds ap-peared, the clock hid behind them.• The sun was setting in a blaze of pink, casting rosy shadows on the undersides of large, wet-looking clouds.• The plane was unable to land due to strong winds and low cloud cover.• A band of cloud stretched low across the valley and it was raining slightly.• Above shone the stars and the rings; below lay a dimly visible sea of clouds.• There wasn't a single cloud in the sky.• All the buildings shook, and at the same time a forked tongue of flame burst upward through the cloud.• These clouds are unbroken, and never, for example, look like the billowy cumulus clouds of the Earth.• As the road climbed upward, gray-white cloud veils drifted among the dales, chiffon scarves of some giant Isadora Duncan.heavy/thick/dense etc clouds• Under dark, heavy clouds, I returned to the den on the river.• Dark clouds rolled over denser, thicker clouds and merged with them.• Standard polyurethane foam ignites rapidly, forming dense clouds of smoke and toxic vapour as it does so.• By morning thick clouds drift over, but the sky between them is deep blue and occasionally the sun peeks through.• Looking northwards towards the end of the dale, she frowned to see the accumulation of heavy clouds above the moors.• Weather satellite images of the area taken from synchronous orbit show an immense circular area of dense clouds above the impact site.• The sun was down, but there was still light buried in the thick clouds patrolling the sky.• Unfortunately the fireworks must have seeded the thick clouds overhead because it absolutely poured with rain, and we got soaked.cloud of dust/smoke/gas etc• Then in a cloud of dust he was gone.• Another chunk of wall collapsed, sending up a billowing cloud of dust.• Standard polyurethane foam ignites rapidly, forming dense clouds of smoke and toxic vapour as it does so.• As long as a comet nucleus is still active, fresh clouds of dust are emitted at each perihelion passage.• The fire sent up a huge cloud of smoke visible from San Francisco, 40 miles to the south.• Instead it is a massive cloud of dust, radiating 99% of its energy at far infrared wavelengths.• Above the bare-branched trees on the edge of his vision he could see clouds of smoke.• Decades of wallpaper peeling under clouds of dust.cloud of• Businesses are worried by the clouds of a possible trade war.cloudcloud2 verb 1 THOUGHTS/MEMORIES[transitive]CONFUSED to make someone less able to think clearly or make sensible decisionscloud somebody’s judgment/mind/vision etc Don’t let your personal feelings cloud your judgement. Fear had clouded his vision.2 FACE[intransitive, transitive] (also cloud over)SAD/UNHAPPY if someone’s face or eyes cloud, or if something clouds them, they start to look angry, sad, or worried Ann’s eyes clouded with the pain. Then suspicion clouded his face.3 SPOIL something[transitive]SPOIL to make something less pleasant or more difficult than it should have been Her happiness was clouded by having to leave her son behind.Grammar Cloud is usually passive in this meaning.4 → cloud the issue/picture etc5 GLASS[intransitive, transitive] (also cloud up)SEE if glass or a liquid clouds, or if something clouds it, it becomes less clear and more difficult to see through windows clouded up with steam The water clouded and I could no longer see the river bed.6 COVER WITH CLOUD[transitive]COVER to cover something with clouds Thick mist clouded the mountain tops. → cloud over→ See Verb tableExamples from the Corpus
cloud• The fact that you have enjoyed a few jars together will not cloud a journalist's judgement.• The decision to put a parent in a nursing home can be clouded by guilt.• But her happiness is clouded by having to leave daughter Amber behind.• But images of the period are shrouded in myth and clouded by partisan rhetoric.• The team's victory was clouded by the tragic events in their hometown.• Bethany poised over the bed, a slight abstract frown clouding her face.• Alcohol had clouded his judgment.• When I got back to the cabin the sky had started to cloud over.• However, the shadow of war was beginning to cloud the cricket world.• His face clouded when he saw her.• The display cases were clouded with dust.cloudcloud3 adjective [only before noun] using or related to cloud computing cloud storage of dataOrigin cloud1 Old English clud “rock, hill”; because some clouds look like rocks 