What does « Lightning / To shine » mean in the Quran?

Or [it is] like a rainstorm from the sky within which is darkness, thunder and lightning. They put their fingers in their ears against the thunderclaps in dread of death. But Allah is encompassing of the disbelievers.

The lightning almost snatches away their sight. Every time it lights [the way] for them, they walk therein; but when darkness comes over them, they stand [still]. And if Allah had willed, He could have taken away their hearing and their sight. Indeed, Allah is over all things competent.

It is He who shows you lightening, [causing] fear and aspiration, and generates the heavy clouds.

Do you not see that Allah drives clouds? Then He brings them together, then He makes them into a mass, and you see the rain emerge from within it. And He sends down from the sky, mountains [of clouds] within which is hail, and He strikes with it whom He wills and averts it from whom He wills. The flash of its lightening almost takes away the eyesight.

And of His signs is [that] He shows you the lightning [causing] fear and aspiration, and He sends down rain from the sky by which He brings to life the earth after its lifelessness. Indeed in that are signs for a people who use reason.