to rain, or to make something wet with liquid falling on it
TranslatabilityApproximateCertaintySettled
The picture behind this verb is simple: liquid comes down onto something and leaves it wet. Usually that liquid is rain and the thing left wet is the ground, so English Bibles simply say "rain." Matthew 5:45 puts God in charge of it, sending rain on good people and bad alike. James 5:17 reports the flat fact that no rain fell on the land for three and a half years. Revelation 11:6 lets the rain (ὑετός) itself be the thing that comes down.
From there the word reaches in two directions. It can bring down from the sky something that is not water at all: in Luke 17:29 what falls on Sodom is fire and sulfur, in wording borrowed from the older Greek version of the Sodom story. And it can leave the weather behind entirely: in Luke 7 a woman's tears fall on Jesus' feet until they are wet, and Luke reaches for this same verb rather than a word for washing someone clean (νίπτω).
Greek keeps the action and the water separate. This verb is the coming down; the rain that comes down is named by its own words, the ordinary one in Revelation 11:6 and James 5:18, and a close relative of this verb (βροχή) for the downpour that beats against the two houses in Matthew 7:25 and 27.
Nuances
1arain falling on the land, whether it simply falls or God sends it
TranslatabilityDirect
Mat 5:45Jas 5:17 (2×)Rev 11:6
1bto rain down on people something other than water, as a judgment out of the sky
Names the act of sending water down rather than the water itself, and the one doing the sending is God: he "sends rain" on the just and the unjust alike, and he holds it back when Elijah prays that it would not rain.Mat 5:45Jas 5:17
What falls does not have to be water. The same word describes the fire and sulfur that came down on Sodom, so it can carry the sense of a destroying downpour rather than a refreshing one.Luk 17:29
It can leave the sky altogether and simply mean soaking something at close range: the woman at the meal wets Jesus' feet with her tears, which is why English versions here say "wet" or "wash" instead of "rain".Luk 7:38Luk 7:44
Both
Both belong to the same picture of rain falling from the sky, and they can be used side by side in one sentence: the two witnesses shut the sky so that no rain falls during the days of their prophesying.Rev 11:6
Both treat rain as something God controls and answers prayer about. In one short account Elijah prays that it would not rain, and then heaven gives the rain back.Jas 5:17Jas 5:18
Names the rainfall itself as a thing that can be handed over and taken in: God gives "rains from heaven" as evidence of his kindness, and ground is described as drinking the rain that falls on it.Act 14:17Heb 6:7
It is the ordinary weather word, the rain people stand out in and the seasonal rain a farmer waits through: the cold downpour that soaked the shipwrecked party on Malta, and the early and late rains that have to come before there is a harvest.Act 28:2Jas 5:7
βροχήa close relative of this verb naming one particular downpour, used only of the storm that beats against the two houses
νίπτωwashing part of the body clean, where this word claims only that something was made wet
This is the weather word. Its usual subject is the sky, and what it describes is rain falling on a landscape rather than anything a person does with a basin of water.Mat 5:45Jas 5:17Rev 11:6
It belongs to scenes about power over the sky: God sends rain on good and bad alike, a prayer shuts the rain off for years, and witnesses are given authority to stop it.Mat 5:45Jas 5:17Rev 11:6
What comes down is not always water. The same word covers fire and burning sulfur falling on Sodom, so it names the falling itself and takes its character from whatever is falling.Luk 17:29
When it does describe a person, it means soaking or drenching, and the striking thing is the sheer quantity of liquid rather than any idea of getting something clean.Luk 7:38Luk 7:44
Both
Both can describe liquid brought to another person's feet during a meal, one word for the tears that soaked them and the other for the water that washed them, and in both scenes the act is a startling display of humility.Luk 7:38Luk 7:44Jhn 13:5Jhn 13:14
This word is always about washing one named part of the body. The text says which part: hands, face, eyes, feet.Mat 6:17Mat 15:2Jhn 9:7Jhn 13:5
It carries the weight of custom and purity, so skipping it can be turned into an accusation and doing it can settle whether a person counts as clean.Mat 15:2Mrk 7:3Jhn 13:10
It works as an instruction with a result attached: a man is told to go and do it, he does, and he comes back able to see.Jhn 9:7Jhn 9:11Jhn 9:15
Because it is a servant's job, it becomes a standing picture of humble service, listed among the good works that recommend a widow and pressed on the disciples as a pattern.1Ti 5:10Jhn 13:14
brechō in the other biblical languages
מָטַרHebrew“to rain”the Hebrew verb for sending rain, and the word used when the LORD rains sulfur and fire on Sodom in Genesis 19:24
It can mean to wet or moisten something directly with liquid, not just water falling from the sky. When the weeping woman wet Jesus' feet with her tears, this is the verb used.Luk 7:38Luk 7:44
Both
Both name ordinary rain, the weather sent (or withheld) from the sky.Jas 5:17Gen 2:5
Both describe God raining down fire and brimstone in judgment. The New Testament word looks straight back to the Sodom account, using this verb for the same event.Luk 17:29Gen 19:24
It is used for God raining down food from heaven as provision: the manna, the bread, and the meat sent to feed Israel in the wilderness.Exo 16:4Psa 78:24Psa 78:27
רָוָהHebrew“to quench”Hebrew for being soaked or watered through, matching the drenching side of this word rather than the weather side
The Greek word looks up at the sky and names what it sends, so what comes down does not have to be water at all. Fire and burning sulfur falling on Sodom are described with the same verb, rendered "rained" there.Luk 17:29
Because it names rain as an event heaven starts, it is also the word used when heaven is shut and nothing falls at all. Elijah prayed and it did not rain for three and a half years, and the two witnesses are given power to keep the sky closed.Jas 5:17Rev 11:6
It reports the arrival of the water, not how much anything soaked up. God sends rain on the good and the evil without measuring either, and the word says only that the rain came.Mat 5:45
Both
Both words cover water coming down from the sky onto the ground, which is why each carries the ordinary talk about rain in its own Testament. Isaiah says the rain and snow come down and give the earth its drink, and Jesus says God sends rain on everyone alike.Isa 55:10Mat 5:45
Both can leave the weather behind and describe tears making something wet: a prophet weeping over a ruined town until it is drenched, and a woman weeping until Jesus' feet are wet.Isa 16:9Luk 7:38
The Hebrew word stands with whoever receives, filled until there is nothing more to want. Guests take in all the good of God's house, and a tired person is restored to the point of having had enough.Psa 36:8Jer 31:25
It is at home in the language of appetite and desire, where having your fill of something good is the whole point: a wife's love that keeps a husband satisfied, or lovers who mean to take their fill of each other.Pro 5:19Pro 7:18
The same idea turns grim without changing its shape. A sword drinks until it is full, the ground is soaked through with blood, and a suffering man is made to swallow bitterness until he can hold no more.Isa 34:5Jer 46:10Lam 3:15
It runs in both directions at once, which lets a proverb say that the person who refreshes others ends up refreshed himself.Pro 11:25
What scholars say about brechō
The classical sense of βρέχω is "to wet, moisten" (LSJ s.v.); the meteorological sense "to rain, send rain" is a Hellenistic development, standard in the Septuagint and dominant in the New Testament, where five of the seven occurrences describe something falling from the sky. BDAG divides the entry accordingly: (1) to cause rain to fall, whether with God as subject (Matthew 5:45), used impersonally (James 5:17), or with ὑετός as the subject (Revelation 11:6); and (2) to cause to become wet (Luke 7:38, 44). Luke 17:29 reproduces the Septuagint wording of Genesis 19:24, where this same verb rains sulfur and fire on Sodom, so the allusion is lexical as well as narrative. The older transitive sense survives alongside the newer meteorological one in Koine usage, which is why Luke can use the verb of a woman's tears in one chapter and of fire from heaven in another. No occurrence is textually or semantically in doubt.
Sources
BDAG, s.v. βρέχωlexicon
LSJ, s.v. βρέχωlexicon
H. Balz and G. Schneider, eds., Exegetical Dictionary of the New Testament, s.v. βρέχωdictionary
J. P. Louw and E. A. Nida, Greek-English Lexicon of the New Testament Based on Semantic Domains, s.v. βρέχωlexicon