periphery

noun

1. The outside boundary, parts or surface of something.

   “The suburbs are a city's periphery.”

   “Tumor location was concentrated in the macula and superonasal periphery in patients 13.2 months.”

   “The phrase 'Imperial Manila' is used throughout the archipelago to denote the capital-heavy decision-making and the imposition of the will and culture of the political and economic centre on the peripheries.”

2. A first-rank administrative division of Greece, subdivided into provinces.
3. The more anomalous and infrequent aspects of a language, as opposed to the frequent and regular core aspects.