The 1800s (pronounced "eighteen-hundreds") was a decade of the Gregorian calendar that began on January 1, 1800, and ended on December 31, 1809. The term "eighteen-hundreds" can also mean the years between 1800 and 1899 (the years beginning with "18"), and is almost synonymous with the 19th century (1801–1900). This article refers to the decade comprising 1800–1809.