*SET-U

English word origin

Etymology of FiO2

Initialism of fraction [of] inspired + O₂ (“oxygen”). Etymology tree Old French fraccionbor. Middle English fraccioun English fraction Proto-Indo-European *h₂ep Proto-Indo-European *-o Proto-Indo-European *h₂epó Proto-Ge

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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

Initialism of fraction of inspired oxygen.

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

Initialism of fraction [of] inspired + O₂ (“oxygen”). Etymology tree Old French fraccionbor. Middle English fraccioun English fraction Proto-Indo-European *h₂ep Proto-Indo-European *-o Proto-Indo-European *h₂epó Proto-Germanic *ab Proto-West Germanic *ab Old English æf Old English of Middle English of English of English inspired Proto-Indo-European *h₂eḱ-der.? Ancient Greek ὀξύς (oxús) Proto-Indo-European *ǵenh₁- Proto-Indo-European *-os Proto-Indo-European *ǵénh₁os Proto-Hellenic *génos Ancient Greek γένος (génos) French oxygènebor. English oxygen English FiO2

Inspect preserved source fields

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

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      "expansion": "Initialism of fraction [of] inspired"
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    ],
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      "inspired",
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    ],
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      "O₂#Translingual"
    ],
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    ],
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      "fraccioun#Middle_English:_fracture"
    ],
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    ],
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    ],
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    ],
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      "*h₂epó",
      "Reconstruction:Proto-Indo-European/h₂epó#Proto-Indo-European:_away"
    ],
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      "*ab",
      "Reconstruction:Proto-Germanic/ab"
    ],
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      "*ab",
      "Reconstruction:Proto-West Germanic/ab#Proto-West_Germanic:_of"
    ],
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      "æf",
      "æf#Old_English:_of"
    ],
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    ],
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    ],
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    ],
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    ],
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    ],
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      "ὀξύς",
      "ὀξύς#Ancient_Greek:_sharp"
    ],
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      "*ǵenh₁-",
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    ],
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    ],
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    ],
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      "oxygen",
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    ]
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  "references": [],
  "descendants": [],
  "lexical": [
    {
      "pos": "noun",
      "glosses": [
        "Initialism of fraction of inspired oxygen."
      ],
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        "initialism"
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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 FiO2 →

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-RmlPMg