Which invention is Eli Whitney best known for?

Eli Whitney is best known for inventing the cotton gin in 1793, a device that revolutionized the cotton industry by significantly speeding up the process of separating cotton fibers from seeds. This invention greatly increased cotton production in the United States and had a profound impact on the economy and the expansion of slavery in the South. Whitney is also recognized for his role in promoting the concept of interchangeable parts in manufacturing.