1in·ter·state 
/ˌɪntɚˈsteɪt/ adjective
always used before a noun /ˌɪntɚˈsteɪt/ adjective : relating to or connecting different states : existing or occurring between states especially in the U.S.
▪ an interstate highway ▪ interstate commerce/transportation
▪ an interstate highway ▪ interstate commerce/transportation
