to burn something up: to destroy it with fire until nothing of it is left.
TranslatabilityApproximateCertaintySettled
The plain verb behind this one, καίω, is content to mean lighting a lamp or keeping a fire going. This word adds a prefix that means "all the way," and that changes everything: whatever it touches is finished. A stack of scrolls, a third of the world's trees, a great city, the carcass of a sacrificed animal. Each of them ends as ash.
The New Testament reaches for it in three settings:
plain destruction, as when the believers at Ephesus piled their books of spells on a fire and let them go, or when a city is described going up in flames
the standing picture of God's final reckoning, where chaff from the winnowing, weeds bundled at harvest, and a builder's shoddy work all meet the same fire
the law of the sin offering, where the animal's body was carried outside the camp and burned to nothing
What holds those three together is the outcome rather than the flame. This word never describes a fire that simply keeps going, and never heat that scorches a surface without destroying it (καυματίζω). It names fire that finishes its work, which is why English "burn up" fits it better than plain "burn."
Nuances
1ato burn a thing up so that it is destroyed: fire put to an object, to growing things, or to a whole place until nothing of it remains.
TranslatabilityDirect
Act 19:19Rev 8:7 (3×)Rev 17:16*Rev 18:8*
1bto burn up what is worthless when God settles accounts: the recurring picture of chaff, weeds, or poor work destroyed by fire at the end.
Mat 3:12Mat 13:30*Mat 13:40Luk 3:171Co 3:15
1cto burn a sacrifice up entirely: the whole body of the animal reduced to ash away from the camp, as the law for the sin offering directed.
the Greek word also does formal duty for a sacrifice burned whole away from the camp, a solemn use for which English "burn up" sounds too offhand.Heb 13:11
Both
both name fire that leaves nothing of what it took hold of.Rev 8:7Mat 13:40
Only burn up
in everyday English "burn up" often means using something up loosely (fuel, calories, time) or losing one's temper, none of which the Greek word carries.
the Greek word always points past the flame to the object's end, so where a version prints only "burn" the reader can miss that the thing is completely destroyed.Mat 3:12Act 19:19
Both
both describe fire taking hold of something and doing it damage.Rev 17:16
Only burn
English "burn" also covers a lamp burning through the night, a hand burned on a stove, and a fire that is merely alight, and the Greek word describes none of those.
“consume”
Comparison data is not available for this English gloss yet.
“burn completely”
Comparison data is not available for this English gloss yet.
How katakaiō differs from similar Greek words
καίωthe plain verb for setting something alight or keeping it burning, used of a lamp left lit or a fire still going, with no suggestion that the thing is used up; this word says the object is consumed.
Means burning something up until nothing is left, so whatever it names is gone afterward: chaff, trees, and green grass all disappear in the fire.Mat 3:12Luk 3:17Rev 8:7
Names burning as a deliberate act of disposal, where things are gathered up or carried outside on purpose so that fire can get rid of them for good.Mat 13:30Act 19:19Heb 13:11
Describes the total ruin of a city or a person under judgment, where the point is what has been lost rather than the sight of the flames.Rev 17:16Rev 18:8
Can be used of a believer's work failing the test of fire, so the person himself is saved while everything he built is gone.1Co 3:15
Both
Both describe real fire consuming plants that have been gathered for burning, and English says only "burned" for each, so the difference between fire that keeps blazing and fire that leaves nothing behind does not show in translation.Jhn 15:6Mat 13:40
Both belong to the language of final judgment, and Revelation uses each of them: one for fire that falls and burns things away, the other for the fire that never stops burning.Rev 19:20Rev 8:7Rev 17:16
The regular word for lighting a lamp and keeping it lit, so many of its uses are about a flame kept going for the sake of its light rather than fire that destroys.Mat 5:15Luk 12:35Jhn 5:35Rev 4:5
Pictures fire simply as blazing away, with no thought of the fuel running out, which is why it fits a mountain wrapped in flame, a falling star alight like a torch, and a lake that goes on burning.Heb 12:18Rev 8:8Rev 8:10Rev 21:8
Stretches to warmth felt inside a person: the two disciples said their hearts were burning while Jesus opened the Scriptures to them on the road.Luk 24:32
πυρόωto be on fire or to be refined in fire, used of metal purified and of feelings blazing up, so its interest is in the burning state or the refining, not in the object being destroyed.
Names fire that finishes a thing off: what goes in is consumed and nothing usable is left. The chaff and the weeds are deliberately gathered first and then burned up.Mat 3:12Mat 13:30Luk 3:17
Used of a particular batch of physical things destroyed on purpose: the magic scrolls at Ephesus, the animal carcasses taken outside the camp, a builder's shoddy work that does not survive the test.Act 19:19Heb 13:111Co 3:15
Carries the sense of a sentence carried out on a city or a person, where the fire is the end of them and the ruin is final.Rev 17:16Rev 18:8
Both
Both describe literal fire at work in scenes of God's judgment on the world, with no softening of the heat.Rev 8:72Pe 3:12
English Bibles render both with the plain verb "burn", so the difference between being consumed away and being set aflame or refined rarely shows on the page.1Co 3:151Co 7:9
Describes fire as a state someone is in rather than an act done to something: a person can burn inwardly with sexual desire, or with distress over what is happening to others.1Co 7:92Co 11:29
Covers the refiner's fire, where the whole point of the heat is to purify and prove rather than to destroy: gold worth buying because it came through the furnace, and metal glowing white from the forge.Rev 3:18Rev 1:15
Can mean simply set alight, so that the burning thing keeps its shape and does its work while it flames: arrows shot while they are on fire.Eph 6:16
καυματίζωto scorch: heat that burns and injures a surface while what it touches survives, the opposite emphasis from this word, where nothing survives.
This is fire that finishes the job: what it takes hold of is consumed outright, so nothing usable is left. The chaff, the weeds, and the scrolls of magic all simply cease to be.Mat 3:12Mat 13:30Act 19:19
Someone lights it on purpose, for a reason: enemies set a city on fire, and the carcasses of the sacrifices are burned away outside the camp. It names a deliberate act, not a condition of the weather.Rev 17:16Rev 18:8Heb 13:11
Because what it touches is gone for good, this word can measure a total loss: a builder's work goes up in flames while the builder himself survives, and a third of the trees are wiped out.1Co 3:15Rev 8:7
Both
Both belong to scenes of judgment where fire or searing heat is the instrument and those it falls on cannot get away from it.Rev 18:8Rev 16:8
Both describe growing things ruined by heat in the parables about a field: weeds bundled up for the fire, and shoots dried out by the risen sun.Mat 13:30Mat 13:6
This is heat that sears what it falls on without destroying it. The young shoots are still standing when the sun has burned them, and they die from having no root rather than from being consumed.Mat 13:6Mrk 4:6
Its source is blazing heat beating down from above, above all the sun, rather than a fire anyone kindled. Even in the plague vision it is the sun that is given the power to burn people.Rev 16:8Mat 13:6
What it burns is left alive to feel the pain. The people it sears are still able to react, and they curse God instead of turning to him.Rev 16:9
katakaiō in the other biblical languages
שָׂרַףHebrew“to burn”the standard Hebrew verb for burning something up, used of cities, idols, bodies, and sacrifices, and the word the Greek translators of the Old Testament most often turned into this one.
covers ritual and cultic burning: the prescribed incineration of sacrifice remains, sin-offerings, and unclean items according to Torah lawLev 4:12
used for burning cities, idols, and enemy property in warfare and covenant enforcement, where the burning signals total conquest and purgeJos 6:24
applied to burning as a form of judicial execution in the Law and historical narrativesGen 38:24
בָּעַרHebrew“to burn: burn”the Hebrew verb that leans on the fire itself catching and blazing, and that stretches to kindling a fire and to clearing something away, where this Greek word keeps its eye on the object being consumed.
יָצַתHebrew“to kindle”the Hebrew verb for setting something alight, starting the blaze in a field or at a city gate, and for anger flaring up, with its attention on the ignition rather than on the ruin this Greek word describes.
Stresses burning something up completely, consuming it to nothing. The chaff, the weeds, and the scrolls of magic are all reduced to ash, so the word carries a note of final destruction.Mat 3:12Mat 13:40Act 19:19
Often frames the fire as judgment falling on the wicked or on a doomed city, with the outcome that the target is wholly consumed.Rev 17:16Rev 18:8
Both
Both describe destroying a city or building by fire, so a reader meets each when a place is put to the flames.Rev 18:8Jos 8:8
Stresses the act of kindling: setting something alight, starting the blaze in a field, a city, or its gates, with attention on ignition rather than on the finished ruin.Jos 8:192Sa 14:30Jer 17:27
Turns easily to a figure for anger flaring up, so God's wrath is said to be kindled against a place, a use the Greek word does not carry.2Ki 22:132Ki 22:17
The burning is a deliberate job someone does: an agent gathers what is to be destroyed and puts it to the fire, whether chaff swept up at the threshing floor (Matthew 3:12), weeds bundled at harvest (Matthew 13:30), or scrolls of magic piled up in public (Acts 19:19).Mat 3:12Mat 13:30Act 19:19
The fire sorts as well as destroys: what is worth keeping is set aside and only the remainder goes into the flames, as with a harvest divided between the barn and the fire (Luke 3:17), or a builder's work tested so that the worthless part is burned while the builder himself is saved (1 Corinthians 3:15).Luk 3:171Co 3:15
What it burns is a definite object handed over to the fire and reduced to nothing, such as an animal's body carried outside the camp (Hebrews 13:11) or a whole city left in ashes (Revelation 18:8).Heb 13:11Rev 18:8
Both
Both belong to the language of judgment, where fire is what finally deals with the wicked: weeds gathered and burned at the close of the age (Matthew 13:40), and the flame that burned up the rebels in the wilderness (Psalm 106:18).Mat 13:40Psa 106:18
Both are used of fire sweeping over growing things, so that grass and trees are what goes up: a third of the earth with its trees and all the green grass (Revelation 8:7), and a flame racing over a wooded hillside (Psalm 83:14).Rev 8:7Psa 83:14
The flame itself is what acts: fire, a flame, or a fiery breath is the subject doing the burning, so coals catch light from a creature's breath (Job 41:21) and fire goes ahead of God to burn up his enemies (Psalm 97:3).Job 41:21Psa 97:3
It pictures how far a blaze runs and what it scorches along the way: down to the roots of the mountains (Deuteronomy 32:22), across open pasture and woodland (Joel 1:19), leaving a burnt track behind an advancing army (Joel 2:3).Deu 32:22Jol 1:19Jol 2:3
It can describe a being or a person as itself blazing, without naming anything that gets destroyed: God's servants are called "a flaming fire" (Psalm 104:4), and the psalmist lies down among people who are aflame with hostility (Psalm 57:4).Psa 104:4Psa 57:4
What scholars say about katakaiō
The lexicons treat this as a single lexical item, the common verb for burning compounded with a prefix that here carries a completive force, yielding "burn down, burn up, consume by fire." BDAG organizes the New Testament material by object rather than dividing the verb into distinct senses: the chaff and weeds of the Synoptic judgment sayings, the magical books of Acts 19:19, the sacrificial bodies of Hebrews 13:11, and the passive constructions of 1 Corinthians 3:15 and Revelation (BDAG, s.v.). LSJ documents the same range in classical and Hellenistic usage and lists separately the technical use for burning a sacrifice whole (LSJ, s.v.). Friedrich Lang's treatment of this word group in TDNT stresses that the compound denotes total consumption, and traces its heavy Septuagint employment, where it is the regular equivalent of the Hebrew verb for burning up, including in the sin-offering legislation of Leviticus 4:12 and 16:27 that stands behind Hebrews 13:11. Commentators on the Baptist's threshing-floor saying, Davies and Allison on Matthew and Nolland on Luke, read the burning of the chaff as an image of final judgment rather than as agricultural reportage, and note that the accompanying adjective (rendered "unquenchable") qualifies the fire rather than describing the duration of the chaff. Aune's commentary on Revelation connects the burning of the woman in 17:16 both to the penalty of Leviticus 21:9 and to the conventional biblical description of a captured city's fate. Nothing in the literature disputes the verb's meaning; the live questions concern the referent of the fire in 1 Corinthians 3:15 and the theological weight readers place on the judgment sayings.
Sources
BDAG (Bauer, Danker, Arndt, Gingrich), A Greek-English Lexicon of the New Testament and Other Early Christian Literature, 3rd ed., s.v. κατακαίωlexicon
LSJ (Liddell, Scott, Jones), A Greek-English Lexicon, 9th ed. with revised supplement, s.v. κατακαίωlexicon
Friedrich Lang, "καίω, κατακαίω, καῦσις, καυσόω, καύσων," in Theological Dictionary of the New Testament, ed. Gerhard Kittel, vol. 3theological-dictionary
W. D. Davies and Dale C. Allison, The Gospel According to Saint Matthew, International Critical Commentary, vols. 1 and 2commentary
John Nolland, Luke 1:1-9:20, Word Biblical Commentary 35Acommentary
David E. Aune, Revelation 17-22, Word Biblical Commentary 52Ccommentary
William L. Lane, Hebrews 9-13, Word Biblical Commentary 47Bcommentary
Anthony C. Thiselton, The First Epistle to the Corinthians, New International Greek Testament Commentarycommentary