'Signs' in the Bible

He performs great signs (awe-inspiring acts), even making fire fall from the sky to the earth, right before peoples’ eyes.

And he deceives those [unconverted ones] who inhabit the earth [into believing him] because of the signs which he is given [by Satan] to perform in the presence of the [first] beast, telling those who inhabit the earth to make an image to the beast who was wounded [fatally] by the sword and has come back to life.

for they are [actually] the spirits of demons, performing [miraculous] signs. And they go out to the kings of the entire inhabited earth, to gather them together for the war of the great day of God, the Almighty.