Pitch is the distance from the crest of one thread to the next. Because the vast majority of screw threadforms are single-start threadforms, their lead and pitch are the same. Single-start means that there is only one ridge wrapped around the cylinder of the screw's body.
Definition of metropolis. 1  1 : the chief or capital city of a country, state, or region. 2  2 : the city or state of origin of a colony (as of ancient Greece) 3  3a : a city regarded as a center of a specified activity an industrial metropolis a cattle metropolisb : a large important city one of Europe's great metropolises.
This article lists the most populous cities in the world defined according to a concept of city proper. A city proper is a locality defined according to legal or political boundaries and an administratively recognised urban status that is usually characterised by some form of local government. Cities proper and their boundaries and population data may not include suburbs. World Urbanization Prospects, a UN publication, defines population of a city proper as the population living within the administrative boundaries of a city or controlled directly from the city by a single authority..