son: a male child or descendant; and, by extension, anyone who belongs to or shares the character of a person, group, or thing.
At its core this is the ordinary word for a son, a male child of his parents. From there it reaches naturally to any male descendant, so that a person can be called the son of an ancestor many generations back (Jesus is the son of David and son of Abraham). Most of its uses are this plain family sense.
Greek inherited a Hebrew way of speaking in which "son of" marks belonging or character rather than birth. A "son of peace" is a person open to peace, "sons of light" are people who belong to the light, a "son of destruction" is someone bound for ruin. The phrase names what a person is made of or headed for, not who fathered him. The New Testament uses this idiom constantly, which is why the word ranges so far beyond the nursery.
Two uses carry the heaviest weight. Jesus calls himself "the Son of Man," a title drawn from Daniel that sounds humble but claims authority and a coming role in judgment. And he is confessed as "the Son of God," or simply "the Son," naming a unique relationship to the Father that the New Testament writers guard carefully. Believers are also called sons of God, but as those brought into the family, adopted rather than the Son in that one unique sense.
All of these grow from the one idea of sonship: a relationship that defines who you are. The word does not split into unrelated meanings; it stretches the single notion of being someone's son across family, character, destiny, and the deepest claims the New Testament makes about Jesus.