Coolie labor refers to the system of unskilled labor that emerged in the 19th century, predominantly involving Asian workers, especially from China and India, who were contracted to work in harsh conditions for low wages. This labor system was primarily utilized during significant economic events, like the Gold Rush, where there was a high demand for workers in mines, railroads, and agriculture. The term 'coolie' itself has derogatory connotations and reflects the exploitation and discrimination faced by these workers as they were often subjected to poor working conditions and racial prejudice.