Chino pants are lightweight trousers most commonly made from cotton. While it is common for them to be confused with khakis they are in fact a distinct form of pants that are considered to be much dressier, and appropriate for events that require semi-casual dress.
The name chino refers to the Spanish word for Chinese; the country where the pants were originally made. In China, and the Philippines, chino cloth is commonly used in clothing construction for peasants, so the fact that chino pants are a standard for semi-casual dress events in the western hemisphere is not without irony.
The popularity of Chino pants grew in the 1900s with soldiers returning from the Philippines at the end of the Spanish-American war. It was then that people were first introduced to these lightweight trousers of Chinese descent.
The wide adoption of Chino pants came about during World War II when the military needed ways to conserve fabric. Because Chino pants are tapered at the bottom and contain no pleats it was possible to produce a large number of pants with less fabric.