笼罩 (lǒng zhào) means 'to envelop, to shroud' — used for mist, darkness, atmosphere, or a mood that covers something from above or all around. Unlike 包围 (bāo wéi 'surround, encircle'), which is physical and often military, 笼罩 is intangible and atmospheric. It also differs from 掩盖 (yǎn gài 'cover up, conceal') and 掩饰 (yǎn shì 'mask, hide'), which imply hiding something, and from 罩 (zhào 'cover with a hood'), which is concrete.