Standard time refers to the uniform time system used across different regions to coordinate activities and schedules. It was established to replace local mean time, which varied from place to place. Standard time divides the world into time zones, each typically one hour apart, allowing for consistent timekeeping. The concept of standard time was popularized in the late 19th century, particularly with the expansion of the railroad system. The introduction of the International Meridian Conference in 1884 helped establish the Prime Meridian at Greenwich, England, as the reference point for Coordinated Universal Time (UTC).