English word origin

Etymology of ifdef

A keyword in various programming languages, short for if defined.

1 source sectionBrief source recordWiktionary original ↗

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

A construct in source code that allows another part of the code to run only if a specified identifier is defined in the program.

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

A keyword in various programming languages, short for if defined.

Inspect preserved source fields

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

{
  "templates": [],
  "links": [
    [
      "if",
      "if"
    ],
    [
      "defined",
      "defined"
    ]
  ],
  "references": [],
  "descendants": [],
  "lexical": [
    {
      "pos": "noun",
      "glosses": [
        "A construct in source code that allows another part of the code to run only if a specified identifier is defined in the program."
      ],
      "tags": [],
      "recordId": "99e5547827080e021ef372971e99b62d38602dbe8e116ddbef6a76712a914a84",
      "rawRecordSha256": "0df8eebdc9e79c6a1f1ea72728fd10fd9470e8ea50a2df1726341293f4537d84",
      "sourceRecordOrdinal": 5334408
    }
  ],
  "omittedAuxiliaryFields": {
    "templates": 0,
    "links": 0,
    "references": 0,
    "descendants": 0,
    "lexicalRecords": 0,
    "lexicalSenses": 0,
    "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 ifdef →

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-aWZkZWY