A nut with a built in washer like flange. Tee. A nut designed to be driven into wood to create a threaded hole. Square. A four sided nut. Prevailing torque lock. A non-reversible lock nut used for high temperature applications. K-Lock or Kep. A nut with an attached free-spinning external tooth lockwasher.
adjective. The definition of metropolitan is a city or something related to a city. A city and the immediate locations surrounding it is an example of a metropolitan area.
1540s, belonging to an ecclesiastical metropolis, from Late Latin metropolitanus, from Greek metropolites resident of a city, from metropolis (see metropolitan (n.)). Meaning belonging to a chief or capital city is from 1550s. In reference to underground city railways, it is attested from 1867.