Interstate/ˈɪntərsteɪt/ Definition 1 of 2Pro Tip 1/3Not Internal Interstate refers to between states, not within one state. The trucking company specializes in interstate deliveries. Pro Tip 2/3Government Role Interstate activities often involve federal laws due to their multi-state nature. Interstate commerce regulations are enforced by the government. Pro Tip 3/3Widespread Impact Interstate issues or events can affect more than one state, sometimes nationally. An interstate crime spree made headlines across the country.