It is only the church that would think "cross" when speaking of a king and his kingdom.
Kings are somewhat mythical to us. We know there are still some kings in the world, but they are mostly symbolic. We believe and participate in a world that votes for leaders and imposes term limits on presidents. For the most part, when we think of kings we think of castles and jewels and fairy tales. But I cannot think of a single fairy tale where the king dies a poor man on a cross.
Against those who want to claim the gospels are fairy tales, we have a pretty good defense. The stories aren't what people would create if they are trying to sell people on God. The only way these stories get recorded and passed along is if they're true. The only way anyone speaks of God coming in the flesh in a baby born to an unwed mother and poor parents, then lives his life in unimpressive Nazareth and Galilee caring for those others ignore or despise, then is crucified among criminals, one of whom recognizes that he's king even as he's dying, is if this this is true.
The meanings of king and kingdom are entirely rewritten when Jesus is involved, which is why we'll celebrate that Christ the King rewrites our life's narrative this Sunday.
Please read Luke 23:33-43 as a way of preparing for the culminating worship service of the Church Year. Join us Sunday for something special.