Modern phonetic combination of the letters R and J
Rjay is a modern American invention, likely created as a phonetic spelling of the initials 'R.J.' It follows a contemporary trend of turning initial-based nicknames into formal first names. Because it is a modern coinage, it does not have a traditional etymological root beyond the English alphabet.
Less common today
Rjay isn't in the latest US Top 1000. It last peaked at #7,907 in 2012.
US births per 5-year period, 1990βpresent (SSA data).