Snr is the written abbreviation for senior. It is used after someone's name to distinguish them from a younger member of their family who has the same name.
[mainly British]
...Robert Trent Jones, Snr.
regional note: in AM, use Sr.
Snr in British English
or snr
abbreviation for
senior
senior in British English
(ˈsiːnjə)
adjective
1.
higher in rank or length of service
2.
older in years
senior citizens
3.
of or relating to adulthood, maturity, or old age
senior privileges
4. education
a.
of, relating to, or designating more advanced or older pupils
b.
of or relating to a secondary school
5. US
of, relating to, or designating students in the fourth and final year at college