*SET-U

English word origin

Etymology of slag

Borrowed from Middle Low German slagge, slaggen (“slag, dross”), from Old Saxon *slaggo, from Proto-West Germanic *slaggō, from Proto-Germanic *slaggô, from Proto-Germanic *slagōną (“to strike”) + *-gô (diminutive suffix

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In this entry · 1 source sections

The source etymologies

Wiktionary via Kaikki / Wiktextract

The source reports below are imported and unreviewed by *SET-U. Separate numbered origins and differing source variants are preserved; agreement within this extraction is not independent corroboration.

Unnumbered source etymology

Original entry ↗
noun

Waste material from a mine. · Scum that forms on the surface of molten metal. · Impurities formed and separated out when a metal is smelted from ore; vitrified cinders. · Hard aggregate remaining as a residue from blast furnaces, sometimes used as a surfacing material.

verb

To produce slag. · To become slag; to agglomerate when heated below the fusion point. · To reduce to slag. · To talk badly about; to malign or denigrate (someone).

Selected source glosses provide context, not a complete modern definition inventory

Borrowed from Middle Low German slagge, slaggen (“slag, dross”), from Old Saxon *slaggo, from Proto-West Germanic *slaggō, from Proto-Germanic *slaggô, from Proto-Germanic *slagōną (“to strike”) + *-gô (diminutive suffix). Compare Middle Low German slāgen (“to strike”), since originally the splinters struck off from the metal by hammering, from *slagōn, from Proto-West Germanic *slagōn. Compare also Old Saxon slegi, from Proto-West Germanic *slagi. See also Dutch slak, German Schlacke, Swedish slagg; also compare English slay.

Relationships mentioned by the source

These are extracted mentions, not a timeline or a verified sequence of immediate parents.

This page abbreviates 6 auxiliary source items. The etymology narrative is not shortened. Omission counts are available in the audit fields below; consult the original for complete auxiliary material.

Inspect preserved source fields

Raw extraction fields are retained for auditing. Their order does not establish ancestry.

{
  "templates": [
    {
      "name": "bor",
      "args": {
        "1": "en",
        "2": "gml",
        "3": "slagge"
      },
      "expansion": "Middle Low German slagge"
    },
    {
      "name": "der",
      "args": {
        "1": "en",
        "2": "osx",
        "3": "*slaggo"
      },
      "expansion": "Old Saxon *slaggo"
    },
    {
      "name": "der",
      "args": {
        "1": "en",
        "2": "gmw-pro",
        "3": "*slaggō"
      },
      "expansion": "Proto-West Germanic *slaggō"
    },
    {
      "name": "der",
      "args": {
        "1": "en",
        "2": "gem-pro",
        "3": "*slaggô"
      },
      "expansion": "Proto-Germanic *slaggô"
    },
    {
      "name": "der",
      "args": {
        "1": "en",
        "2": "gem-pro",
        "3": "*slagōną",
        "t": "to strike"
      },
      "expansion": "Proto-Germanic *slagōną (“to strike”)"
    },
    {
      "name": "m+",
      "args": {
        "1": "gml",
        "2": "slāgen",
        "t": "to strike"
      },
      "expansion": "Middle Low German slāgen (“to strike”)"
    },
    {
      "name": "m+",
      "args": {
        "1": "gmw-pro",
        "2": "*slagōn"
      },
      "expansion": "Proto-West Germanic *slagōn"
    },
    {
      "name": "cog",
      "args": {
        "1": "osx",
        "2": "slegi"
      },
      "expansion": "Old Saxon slegi"
    },
    {
      "name": "m+",
      "args": {
        "1": "gmw-pro",
        "2": "*slagi"
      },
      "expansion": "Proto-West Germanic *slagi"
    },
    {
      "name": "cog",
      "args": {
        "1": "nl",
        "2": "slak"
      },
      "expansion": "Dutch slak"
    },
    {
      "name": "cog",
      "args": {
        "1": "de",
        "2": "Schlacke"
      },
      "expansion": "German Schlacke"
    },
    {
      "name": "cog",
      "args": {
        "1": "sv",
        "2": "slagg"
      },
      "expansion": "Swedish slagg"
    },
    {
      "name": "cog",
      "args": {
        "1": "en",
        "2": "slay"
      },
      "expansion": "English slay"
    }
  ],
  "links": [
    [
      "slagge",
      "slagge#Middle_Low_German"
    ],
    [
      "slaggen",
      "slaggen#Middle_Low_German"
    ],
    [
      "*slaggo",
      "Reconstruction:Old Saxon/slaggo"
    ],
    [
      "*slaggō",
      "Reconstruction:Proto-West Germanic/slaggō"
    ],
    [
      "*slaggô",
      "Reconstruction:Proto-Germanic/slaggô"
    ],
    [
      "*slagōną",
      "Reconstruction:Proto-Germanic/slagōną"
    ],
    [
      "*-gô",
      "Reconstruction:Proto-Germanic/-gô"
    ],
    [
      "slāgen",
      "slagen#Middle_Low_German"
    ],
    [
      "*slagōn",
      "Reconstruction:Old Saxon/slagon"
    ],
    [
      "*slagōn",
      "Reconstruction:Proto-West Germanic/slagōn"
    ],
    [
      "slegi",
      "slegi#Old_Saxon"
    ],
    [
      "*slagi",
      "Reconstruction:Proto-West Germanic/slagi"
    ],
    [
      "slak",
      "slak#Dutch"
    ],
    [
      "Schlacke",
      "Schlacke#German"
    ],
    [
      "slagg",
      "slagg#Swedish"
    ],
    [
      "slay",
      "slay#English"
    ]
  ],
  "references": [],
  "descendants": [],
  "lexical": [
    {
      "pos": "noun",
      "glosses": [
        "Waste material from a mine.",
        "Scum that forms on the surface of molten metal.",
        "Impurities formed and separated out when a metal is smelted from ore; vitrified cinders.",
        "Hard aggregate remaining as a residue from blast furnaces, sometimes used as a surfacing material."
      ],
      "tags": [
        "countable",
        "uncountable"
      ],
      "recordId": "5b62dc5ca3f465366fa7705e33eb9708d9e9bc36118347b2da7280074c7f82b2",
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      "sourceRecordOrdinal": 239567
    },
    {
      "pos": "verb",
      "glosses": [
        "To produce slag.",
        "To become slag; to agglomerate when heated below the fusion point.",
        "To reduce to slag.",
        "To talk badly about; to malign or denigrate (someone)."
      ],
      "tags": [
        "transitive",
        "intransitive",
        "UK",
        "slang"
      ],
      "recordId": "93c1b658c044285ff91601a2d93104b5659a238ce4c2b5ac84a25f9bd0daa06f",
      "rawRecordSha256": "782a8139175217d94aa70d7c3ffbb94733948363d88609b1076c2ca3d9eb3c5c",
      "sourceRecordOrdinal": 239568
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  ],
  "omittedAuxiliaryFields": {
    "templates": 0,
    "links": 0,
    "references": 0,
    "descendants": 0,
    "lexicalRecords": 0,
    "lexicalSenses": 6,
    "glosses": 0
  }
}

Where this record stops

This page does not supply an independently verified sound-change sequence, first-use manuscript or complete family tree unless a cited analysis explicitly establishes one. Missing detail here is a limit of this record—not a claim that humanity knows nothing more.

An older meaning does not determine what a word must mean today. Follow the sources, preserve disagreements, and keep ancestry separate from interpretation.

Contribute located evidence for slag →

Source and snapshot

Imported from Wiktionary contributors; extracted by Tatu Ylonen / Wiktextract / Kaikki.org. Selected fields are reformatted and grouped; wording, source identity and etymology sections are retained. CC-BY-SA-4.0 applies to the imported source material.

Dump: 2026-10-01 · Extracted: 2026-10-30. These are snapshot dates, not the word’s first attestation or the page’s revision date.

Source entry and bibliography ↗Wiktionary revision history ↗Acquisition and rights ledger
Machine-source provenance
Source SHA-256
5ff2c072f8099f2d2ce484bd6957bf179f046d2ad37bc36555edf8bb84cb5291
Import run
73216b9a9b78ed3830994bf853103716f5a4dc57099e371e9f8fdc468facca26
Permanent entry ID
w-c2xhZw