It's not a good idea to get definitions for Greek words and how they were used in Greek literature from an English dictionary as language and definition have changed over time.
I suggest you take another look at the Liddell Scot Jones Greek dictionary which is pretty much the standard in Greek matters:
As for the the earth being destroyed by fire:
(Eccl 1:4 KJV) One generation passeth away, and another generation cometh: but the earth abideth for ever.
I'm pretty sure Peter would be aware of that scripture.
In regards to fire - we need to consider it's figurative usage:
Luke 12:49 KJV) I am come to send
fire on the earth; and what will I, if it be already kindled?
(Luke 12:50 KJV) But I have a baptism to be baptized with; and how am I straitened till it be accomplished!
(Luke 12:51 KJV) Suppose ye that I am come to give peace on earth? I tell you, Nay; but rather division:
(Luke 12:52 KJV) For from henceforth there shall be five in one house divided, three against two, and two against three.
(Luke 12:53 KJV) The father shall be divided against the son, and the son against the father; the mother against the daughter, and the daughter against the mother; the mother in law against her daughter in law, and the daughter in law against her mother in law.
I think it's plain from the above (regardless of the baptism statements) that the fire represented turmoil and "fighting"
(
Mat 10:34 KJV) Think not that I am come to send peace on earth:
I came not to send peace, but a sword.
(Mat 10:35 KJV) For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law.
As can be seen Matthew gives another view of this with the "sword".
Adam Clarke on Matt 34:
Think not that I am come to send peace, etc. - The meaning of this difficult passage will be plain, when we consider the import of the word peace, and the expectation of the Jews. I have already had occasion to remark, (Matthew 10:12), that the word שלום (shalom), rendered by the Greeks ειρηνη , was used among the Hebrews to express all possible blessings, temporal and spiritual; but especially the former.
The expectation of the Jews was, that, when the Messiah should come, all temporal prosperity should be accumulated on the land of Judea; therefore την γην , in this verse, should not be translated the earth, but this land. The import of our Lord‘s teaching here is this, Do not imagine, as the Jews in general vainly do, that I am come to send forth, ( βαλλειν ), by forcing out the Roman power, that temporal prosperity which they long for.
I am not come for this purpose, but to send forth ( βαλλειν ) the Roman sword, to cut off a disobedient and rebellious nation, the cup of whose iniquity is already full, and whose crimes cry aloud for speedy vengeance. See also on Luke 12:49 (note). From the time they rejected the Messiah, they were a prey to the most cruel and destructive factions; they employed their time in butchering one another, till the Roman sword was unsheathed against them, and desolated the land.
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(1 Pet 1:7 KJV) That the trial of your faith, being much more precious than of gold that perisheth,
though it be tried with fire, might be found unto praise and honour and glory at the appearing of Jesus Christ:
The "trial by fire" is speaking of the persecutions.
(2 Pet 3:7 KJV) But the
heavens and the earth, which are now, by the same word are kept in store, reserved unto fire against the day of judgment and perdition of ungodly men.
We need to ask why would the "heavens and the earth" be reserved for fire until the day of judgment of ungodly men unless the "heavens and earth" figuratively represented the Jewish polity and apostate Israel?
What did the heavens and earth do wrong to be destroyed by fire?
The bible is full of poetic descriptions of destruction with "fire"
(Isa 10:17 KJV) And the light of Israel shall be for a fire, and his Holy One for a flame: and it shall burn and devour his
thorns and his briers in one day;
(Ezek 20:47 KJV) And say to the forest of the south, Hear the word of the LORD; Thus saith the Lord GOD; Behold, I will kindle a fire in thee, and it shall devour
every green tree in thee, and every dry tree: the flaming flame shall not be quenched, and all faces from the south to the north shall be burned therein.
Obviously the above is not dealing with vegetation.
(Isa 26:11 KJV) LORD, when thy hand is lifted up, they will not see: but they shall see, and be ashamed for their envy at the people; yea,
the fire of thine enemies shall devour them.