What does "Son" mean?Well, weh ave to say what does Son of man or son of God mean to a 1st century jew, not to us or anyoen else coming after them.
When we interpret something we must try our best to understand what was written, why, for whom and what time frame.
I think:
When Jesus was called Son of Man, it meant that he was the embodiemnt of "man", like the verses in Daniel and Revelations: "one like the son of man".
It was a description, the son of man was a term fo one that represented and embodied the attributes of Man, he looked like "man" even if the person in question wasn't "a man", espcially in the case when the verse "one LIKE' the son of man, which leads us to understand it as a description of appearence.
So when Jesus called himself or was called son of man, it meant that he was an example, an embodiemnt of all that man was, a "prime example, and in a more deeper context in relation to Jesus, all that man CAN become.
So, that same view applied to Son fo God, as he was called by some, means that those using that viewed him as an embodiemnt of "God", just as son of man would mean what I stated above.