Spider-Man: Far From Home - What The Title Means

2. The Alternate Universe Theory

Taking the title a little more literally once more, this theory could tie into the rumours about Avengers 4 being heavily invested in the multiverse (particularly off the back of Ant-Man And The Wasp). And it could well be that the heroes who were "killed" in Infinity War were in fact simply teleported to another reality altogether through the multiverse.

In that sense, Peter would have been "far from home" until he could find his way back in Avengers 4 (assuming he actually does).

Or even more intriguingly, the Peter who we will see in Far From Home might actually BE an alternate universe character who is brought back to the MCU-verse by the heroes who travel through the multiverse in Avengers 4. In essence, he could be a "replacement" who stands in for Peter (perhaps because his own reality has been compromised).

Either way, there's definitely a possibility of some multiverse meaning in there.