English 'itinerary' descends from Late Latin 'itinerārium' (a road guide), from Latin 'iter' (journey, road), from PIE *h₁ey- (to go) — originally the name for the practical route-books that guided travelers across the Roman road network.
A planned route or schedule of a journey, or an account of a journey and its stops.
From Late Latin 'itinerārium' (an account of a journey, a road guide), neuter of 'itinerārius' (of or pertaining to a journey), from Latin 'iter' (genitive 'itineris,' journey, road, way), from the PIE root *h₁ey- (to go). The Romans produced practical itineraria — road guides listing distances between stops along major routes. The most famous surviving
The Roman 'Itinerarium Antonini' listed 225 routes across the Empire with distances between stops, functioning as an ancient GPS. A traveler could look up the route from Londinium (London) to Eboracum (York) and find each stop and its mileage. The word 'ion' in chemistry also derives from the same PIE root *h₁ey- — a Greek participle meaning