'Reigning' in the Bible

The Lord said to Samuel, “How long will you grieve for Saul, when I have rejected him as king over Israel? Fill your horn with oil and go; I will send you to Jesse the Bethlehemite, for I have chosen a king for Myself among his sons.”

But now, behold, Adonijah is [acting as] king; and now [as things stand], my lord the king, you do not know it.

and they are seven kings: five of whom have fallen, one exists and is reigning; the other [the seventh] has not yet come, and when he does come, he must remain a little while.