Avengers: Infinity War - Official Infinity Stone Powers Revealed (And What They Mean)

5. The Time Stone

Power: Set the future, alter the past

Item: The Eye Of Agamotto

Meaning:

Now this is arguably the most telling of all of the Stone descriptions, because it might as well be the actual tag-line for Avengers 4, if rumours of time travel are indeed to be believed. We're led to believe that the survivors will travel back in time (with the help of adapted Pym Tech) in order to undo Thanos' snap, which is clearly the "alter the past" element covered.

And as for "setting" the future... That's a more telling definition that isn't something we've encountered before. We know that Doctor Strange could use the Stone to witness possible futures, but setting and witnessing are entirely different prospects. Could that phrasing reveal that Strange actually did something to set which of the millions of possible futures he saw as the one that will be?

It could be a poetic phrase, but it's certainly pretty telling.

Difference To Comics:

Given what we've seen the Time Stone do already, it's pretty much exactly the same as the Time Gem in the comics, though there are a couple of differences. Notably, we've not seen it grant the user the ability to age and de-age beings. But as with the comic version, the MCU Stone essentially allows its user to be omniscient.