For the law, having a shadow of the good to come, not the very image of the things, … Heb. 10:1 WEB

Learning to sort out types is a necessary skill for understanding prophecy.

Multiple words are used for this earth.

Perhaps the broadest of these is the Hebrew word eretz. Eretz is of course used for what we would call the earth, and is used unambiguously for the whole thing from the first. For instance.

“God called the dry land Earth, and the gathering together of the waters he called Seas. God saw that it was good.”
Gen 1:10 WEB

And that is the word eretz, and it talks about this being formed before the sun was lit (which is not until Genesis 1 verses 14 to 16). Even so there is often more to eretz, for it can be used to describe a “land” in the sense of a nation (much as we might sing, “This land is my land, this land is your land …). Also it can be used to describe land in the sense of, “This my land where my house sits.” Lastly, eretz can be used for land in the sense of earth or ground, as in “This land/ground/dirt is no good. It won’t raise anything.” There are of course other Hebrew words, but eretz is the widest of all that are used.

There are two main words in the New Testament.

Perhaps the broadest of these is the Greek word g?. You might say it is a true Greek equivalent to the Hebrew word eretz. G? can translated as earth, world, land, nation, dirt, etc., much as eretz. But there is another common word used, and that is the word kosmos. Kosmos has the sense of this world in the English sense, but also has the sense of the things and the systems of this world. And there are words in both Hebrew and Greek for what we might call “the inhabited world.”

Of course Peter and others speak of the
destruction of this present world.

Peter says,

“But the day of the Lord will come as a thief in the night; in which the heavens will pass away with a great noise, and the elements will be dissolved with fervent heat, and the earth and the works that are in it will be burned up.”
2Pe 3:10 WEB

Then Peter speaks of an entirely new creation.

“But, according to his promise, we look for new heavens and a new earth, in which dwells righteousness.”
2Pe 3:13 WEB

Which opens the possibility of speaking of more than one “earth.”

Now sometimes this may be very simple.

For instance Isaiah says,

“For, behold, I create new heavens and a new earth; and the former things shall not be remembered, nor come into mind. ”
Isa 65:17 WEB

That seems to be clearly one of the “promises” of a “new heavens and a new earth.” So eretz here seems clearly to be speaking of the new earth.

Other passages may not be near so clear.

WEB is the World English Bible, a copyright free revision
of the original ASV American Standard Version 1901