Sr is a written abbreviation for senior, and is written after a man's name. It is used in order to distinguish a man from his son when they both have the same name.
...Donald Cunningham, Sr.
sr in British English1
symbol for
steradian
steradian in British English1
(stəˈreɪdɪən)
noun
an SI unit of solid angle; the angle that, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to the square of the length of the radius
Symbol: sr
sr in British English2
the internet domain name for
Suriname
Suriname in British English2
(ˌsʊərɪˈnæm) or Surinam
noun
a republic in NE South America, on the Atlantic: became a self-governing part of the Netherlands in 1954 and fully independent in 1975. Official language: Dutch; English is also widely spoken. Religion: Hindu, Christian, and Muslim. Currency: Surinamese dollar. Capital: Paramaribo. Pop: 563 402 (2017 est). Area: 163 820 sq km (63 251 sq miles)