What is the special significance of the term ' signs' in relation to the miracles of Jesus?

We read in Jn 6:26: Jesus answered, “Very truly I tell you, you are looking for me, not because you saw the signs I performed but because you ate the loaves and had your fill. Elsewhere also, John uses the term ' sign' while reporting the miracles of Jesus. In fact, we seldom here Jesus referring to his own deeds as miracles, one exception being Mtt 11:23: And you, Capernaum, will you be lifted to the heavens? No, you will go down to Hades. For if the miracles that were performed in you had been performed in Sodom, it would have remained to this day. My question therefore is: What is the special significance of the term ' signs' in relation to the miracles of Jesus ?