popcorn

Popcorn is a variety of Zea mays with a uniquely hard pericarp that traps steam when heated, building pressure until the kernel inverts and expands to thirty or forty times its original volume. Native peoples of the Americas cultivated and popped this specific variety for at least six thousand years. Archaeological specimens from the coastal Peruvian site of Huaca Prieta, dated to around 4700 BCE, include popped kernels recognizable as popcorn. The Aztec called it momochitl and used it in ritual offerings to the rain deity Tlaloc.

The English compound popcorn first appeared in regional American newspapers around 1819 and entered John Russell Bartlett's Dictionary of Americanisms in 1848. Pop is onomatopoeic, borrowed from the sound the kernel makes when it bursts. Corn in American English already meant maize (Zea mays), narrowed from the older British English sense of any grain. The compound is purely descriptive and purely American in origin.

The industrialization of popcorn began at the 1893 World's Columbian Exposition in Chicago, where Charles Cretors introduced the first commercial steam-powered popcorn machine. Street vendors had been selling popcorn from pushcarts since the 1880s, but Cretors's machine standardized the product and made it portable at scale. Movie theaters adopted popcorn during the Great Depression of the 1930s because the profit margins were high and the price was low enough for audiences reduced to pennies.

The cultural association between popcorn and cinema was essentially complete by 1940, when roughly eighty percent of American movie theaters sold it. Global cinema chains exported the habit worldwide after the 1950s, so that popcorn reached markets where maize had never been a staple. A Mesoamerican food, renamed by a sound, became the international smell of leisure.