English word origin

Etymology of WD-40

Trademark; an abbreviation of "Water Displacement, 40th formula" or "40th attempt" used by Norm Larson of the Rocket Chemical Company of California, the oil's developer.

1 source sectionExtended source reportWiktionary 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 ↗

name

A penetrating oil used as a universal solvent, a lubricant and to protect electric circuits from moisture. · Anything or anyone that has many different uses.

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

Trademark; an abbreviation of "Water Displacement, 40th formula" or "40th attempt" used by Norm Larson of the Rocket Chemical Company of California, the oil's developer.

Inspect preserved source fields

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

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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 WD-40 →

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-V0QtNDA