2 John 1:1 (NLT)
This letter is from John, the elder. I am writing to the chosen lady and to her children, ...
An alternate translation of this phrase: " the chosen lady and to her children, ..." is: "the church God has chosen and its members."
This coded language is used throughout this short letter, so I suspect it is written to a church meeting secretly under dangerous circumstances. If the letter were to be intercepted, there is no way to identify the town or home where the church assembles.
In most western countries it is hard to imagine the dangers faced by Christians. However this threat is familiar even today for Christ's followers who live in places where belief is still outlawed.