/klaʊd ||; klaυd/noun1 [C,U] a mass of very small drops of water that floats in the sky and is usually white or grey 云: The sun disappeared behind a cloud. 太阳躲进云里去了。A band of thick cloud is spreading from the west. 一团密云从西边涌过来。
2 [C] a mass of smoke, dust, sand, etc 一股（烟）；一团（尘埃）；一阵（沙）: Clouds of smoke were pouring from the burning building. 一股股的浓烟从着火的大厦里冒出来。
every cloud has a silver lining even a very bad situation has a positive or hopeful side黑暗中总有一线光明。
under a cloud with the disapproval of the people around you 名声不好；不光彩:
She left her job under a cloud because she'd been accused of stealing. 她不光彩地离职，因为人家说她偷东西。