Could you please explain the meaning of this? I have it in a sentence - The speaker was, by some margin, the youngest person in the room. I am a translator from English to Czech and I can´t find it anywhere. Thanks.
It means by some non-zero or at least non-negligible margin (difference, or delta). IOW, it means that the person was considerably younger than everyone else.
an additional amount or one beyond the minimum necessary.
If the speaker was younger than the others by one year, that would not be a big deal - someone has to be the youngest.
But if he was the youngest by a number of years, that is a significant margin.
By some margin, you are saying, by a number of years.
He was noticeably younger than others. In Czech, this is "zretelne najmladsi".