Banquo says:
"Thou hast it now, King, Cawdor, Glamis, all,
As the weird women Promised, and I fear
Thou play'dst most foully for't: yet it was said
It should not stand in thy posterity,
But that myself should be the root and father
Of many kings."
Act 3, Scene 1, Lines 3–6
What does the word "root" mean in this passage?