| Noun | 1. | interstate - one of the system of highways linking major cities in the 48 contiguous states of the United States |
| Adj. | 1. | interstate - involving and relating to the mutual relations of states especially of the United States; "Interstate Highway Commission"; "interstate highways"; "Interstate Commerce Commission"; "interstate commerce" intrastate - relating to or existing within the boundaries of a state; "intrastate as well as interstate commerce" |