jnr.

Noun

junior (countable and uncountable, plural juniors)

1. (countable) A younger person.
   • four years his junior

   Antonyms:

   senior

2. A name suffix used after a son's name when his father has the same name (abbreviations: Jnr., Jr., Jun.).
3. (uncountable) A clothing size for girls or women.
4. (Philippines, US, countable) A third-year student at a high school or university.
5. (Commonwealth, Ireland, UK, countable) A student in a junior school or the second part of a primary school.
   • My son is now a junior at another, bigger school; but our hopes for his schooling have really remained the same. Of course, we want him to be able to read and keep up at maths but the fact that he is still so enthusiastic about his school and his teacher and his classmates2013 December 19, Michelle MacGrath, The Art of Peaceful Teaching in the Primary School: Improving Behaviour and Preserving Motivation, Routledge, →ISBN
6. (countable) A junior barrister.

See all 18 meanings of junior