The definition you quoted doesn’t contradict purify. Definition one agrees with it. I think we should accept that definition rather than the other definitions that say torture because it agrees with 1 Corinthians.
Each builder must choose with care how to build on it. For no one can lay any foundation other than the one that has been laid; that foundation is Jesus Christ. Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw—The work of each builder will become visible, for the Day will disclose it, because it will be revealed with fire, and the fire will test what sort of work each has done. If what has been built on survives, the builder will receive a reward. If the work is burned up, the builder will suffer loss; the builder will be saved, but only as through fire.
This fits perfectly with the first definition:
to test (metals) by the touchstone, which is a black siliceous stone used to test the purity of gold or silver by the colour of the streak produced on it by rubbing it with either metal
Baptism by fire is a theme in scripture:
But we must always give thanks to God for you, brothers and sisters beloved by the Lord, because God chose you as the first fruits for salvation through sanctification by the Spirit and through belief in the truth. - 2 Thessalonians 2:13
This verse speaks of the Christians who are chosen by grace in this lifetime called the first fruits. They are saved by the Spirit and through faith in the truth. What Paul is saying here is that Christians (first fruits) are saved by belief in this lifetime. I say this lifetime because if Christians are the first fruits then this implies that there are second fruits. The fact that Paul refers to Christians as first fruits and not the “only” fruits shows this. Although Paul tells us that the first fruits are saved by the Spirit and faith he doesn’t tell us how the second fruits will be saved. We do get a clue however in Luke 3:15-17:
As the people were in expectation, and all were questioning in their hearts concerning John, whether he might be the Christ, John answered them all, saying, “I baptize you with water, but he who is mightier than I is coming, the strap of whose sandals I am not worthy to untie. He will baptize you with the Holy Spirit and fire. His winnowing fork is in his hand, to clear his threshing floor and to gather the wheat into his barn, but the chaff he will burn with unquenchable fire.”
According to this passage it’s the unquenchable fire that Jesus baptizes in. This is the Lake Of Fire And Sulfur. In the Bible God can and does use fire not only to punish and correct but to purify. As we have seen from the Lexicon the word usage and meanings in “The Lake Of Fire” make that likely. The Bible elsewhere states that God is the savior of all people. Especially of them that believe. So, some are saved by grace through faith in this lifetime others by fire without faith in the next. They are baptized in fire as they die to self and resurrected to new life. Just as believers are crucified with Christ, die to self as they are baptized and risen to new life. What happens at the cross happens in the lake of fire - judgment, destruction, and resurrection. We see this in passages that speak of the restoration of creation through fire as the fire purges and creates a new heavens and earth. This is how all will be reconciled to God. Faith is for this age not the next. The goats undergo the corrective purification of Christ in the lake of fire in the next. When we all embrace Christ in the next life the faith of the elect will pass away.
“Now faith is the substance of things hoped for, the evidence of things not seen”(Heb.11:1).
“For we walk by faith, not by sight” (2 Cor. 5:7).
Now hope that is seen is not hope. For who hopes for what he sees? - Romans 8:24
“For now we see in a mirror dimly, but then face to face. Now I know in part; then I shall know fully, even as I have been fully known”. (1 Cor. 13:12)
The objects of faith and hope will be fulfilled and perfectly realized in heaven, but love will last forever. In heaven there will be nothing but perfect expression of love towards God and each other. As the Catholic Study Bible states in it’s commentary on 1 Corinthians 13:13-
The translation is misleading because it fails to render the Greek adverb nuni (now). Paul is not saying that all three virtues are eternal, but instead he ties them to the present age. Faith and hope will pass away when we see the Lord in heaven and possess the eternal happiness we yearned for in this life. But “love” never ends (13:8). Rather than passing away, love reaches perfection in the everlasting embrace of the Trinity that awaits the saints beyond this life. (IGNATIUS Catholic Study Bible footnote)