What is the term 'night soil' colloquially referring to?

The term "night soil" colloquially refers to human waste collected at night, typically from privies or latrines in places without proper sewage systems. Historically, this practice was common in urban areas, where sanitation infrastructure was lacking. People would often collect human waste after dark to prevent it from being an eyesore and mitigate odors in residential areas.

The use of night soil has significant historical and cultural connotations, particularly in various countries where it has been utilized as a fertilizer in agriculture. This practice highlights the important relationship between human waste management and environmental health, as improper disposal of sewage can lead to contamination of water sources and public health issues.

In contrast, organic compost materials refer to decomposed plant and food waste, livestock waste originates from farming animals, and used cooking oil pertains to fats from food preparation. Each of these options addresses different waste management aspects, but only "night soil" specifically involves the collection of human waste.