nullah

1. (chiefly South Asia) A stream-bed, ravine, or other watercourse; a drain for rain or floodwater.Examples: "About this time a large gole of horsemen came on towards me, and I proposed to charge; but as they turned at once from the fire of the guns, and as there was a nullah in front, I refrained from advancing after them."; "It was just after the exit from a bridge; the animal had probably come up out of the nullah."; "Until a few years ago, much of the city’s sewage was released untreated into the Ganges via public drains, or nullahs, which discharged along the same bank as the ghats, where people habitually bathe."South-Asia

2. (Hong Kong) An open-air, concrete-lined channel for draining rain or wastewater; a storm drain.Examples: "On all sides, wild mountains rise precipitously above wooded nullahs, and we have a clear view, to the right, of the famous Amah Rock, with its singular resemblance to a Chinese woman carrying her baby on her back in the traditional fashion."Hong-Kong