fire: the burning flame, with all its power to warm, consume, purify, and destroy
Across the New Testament this is one word, fire, used for one thing seen in many settings. At its base it is ordinary flame: the cooking fire in a courtyard, the brushwood thrown on a campfire, a lightning strike. From that single physical reality the writers draw the whole range of what fire does, and the contexts, not the word itself, tell you which side of fire is in view.
Two settings dominate. The first is judgment. Because fire consumes what is worthless and cannot be reversed, it becomes the standard picture of God's final dealing with evil: the chaff burned after the harvest, the fruitless tree thrown into the flames, the fiery furnace, the lake of fire. The second is testing and purifying. The same fire that destroys the worthless also refines metal, burning away impurity and leaving what is genuine, so fire pictures the trials that prove faith real and the day that will test each person's work.
A few places use fire for sheer destructive force in human speech and conduct, most vividly the tongue that James calls a fire setting a whole life ablaze. And fire repeatedly marks the presence of God himself, who appears in the burning bush, descends as tongues of fire at Pentecost, and is called a consuming fire.
These are facets of one idea, not separate words. A reader carries the same mental picture, flame, into every verse; what shifts is what that flame is doing.