Q: When did we change from saying “around the world” to “across the world”? Doesn’t “across” contradict our notion that the world is round?
A: “Across” doesn’t always mean in a straight line. It can also mean distributed “throughout, all over, in all or many parts,” according to the Oxford English Dictionary.
Similarly, “around” doesn’t just mean encircling something. It can also mean in “every direction from a central point; on every side, all about.”
So we see nothing wrong with the phrase “across the world.” (We also have no quibble with “across the globe,” and “globe” implies roundness even more than “world.”)
As for actual usage, “around the world” is overwhelmingly more popular than “across the world,” according to a comparison of the two phrases in the millions of books tracked by Google’s Ngram Viewer.
As you can see, “around” leaves “across” in the dust and continues to trend upward in the latest results. Breakdowns of British and American English show much the same results.
For the bigger picture—use on the Internet up until today—simple Google searches also show “around the world” is way ahead: And for what it’s worth, “around the globe” leads “across the globe.”
So whether people are talking about the world or the globe, they prefer “around” to “across.” But as we said, there’s nothing wrong with “across” in this context.
The Ngram comparison we mentioned above shows that both “around the world” and “across the world” are found in writing published since at least as far back as 1800.
In our own searches, we haven’t found any examples of “across the world” older than 1800, but we found “around the world” in an obscure play first acted in 1680.
Here’s the rather overwrought passage, from Elkanah Settle’s tragedy Fatal Love: or, The Forc’d Inconstancy:
Nay, tho you scatter all my sprinkled Ashes
Around the World, each Atom of my Dust
Shall find a Soul, and flye into his Bosom.
from Grammarphobia http://www.grammarphobia.com/blog/2017/04/across-around.html