The next question is "what does junior mean" and "what does senior mean".

There's always another question

If you're looking for a "junior" and you don't know what a "junior" means, then that's your problem, no? I mean, if you are willing to pay X for position Y, you (your company) should know exactly what you are looking for.

Otherwise you are just fishing and see what happens. Not bad, though, but I don't think that's an excuse for "can't list salaries in job ads"

The concern isn't knowing that "junior" mean. The concern is explaining it well in 150 words or less.