.def
5 claimants
5 primary
0 secondary
shared primary (5)
SWH popularity
From the SWH-MSR-ARV dataset (Desmazières, Di Cosmo, Lorentz, MSR 2025; file nb_extensions_alphanum.csv) — one row per (ext, year) in the full SWH archive. Case-aggregated. citation.
959.2K
total occurrences
252.5K
since 2019 (26.3%)
1970–2023
years active
Case variants in archive: .def (934.8K), .DEF (22.6K), .Def (1.8K), .DeF (1), .dEf (1), .DEf (1) — aggregated above.
Attribution status
This extension is attributed to D; linux-kernel-module; Modula-2; NMODL; Singularity as primary by 5 authoritative claims.
Authoritative sources: ✗ Linguist · no claim ✓ Pygments ✓ Wikidata · Q319268 △ Wikipedia · secondary
Claimants (6)
Languages that list
.def among their extensions. Strength reflects whether the upstream source treated it as their primary extension.| Language | Source | Strength |
|---|---|---|
| D | wikidata | primary |
| linux-kernel-module | pygments | primary |
| Modula-2 | pygments | primary |
| NMODL | pygments | primary |
| Singularity | pygments | primary |
| Modula-2 | wikipedia | proposed |
Wikidata says… (12)
File formats, image formats, audio codecs and other non-PL
entities that claim
.def on Wikidata
(property P1195) or in the Wikipedia infobox.
Source: data/derived/external_extension_index.csv.
Click Use as new PL on any row to open the
Add-PL form pre-filled with that entry's name, Wikipedia/Wikidata
URL, and this extension — one submission creates the PL + claim.
| Format | Class (Wikidata P31) | Suggested label | MIME | Notes | Action |
|---|---|---|---|---|---|
| 22DISK format Definition Q105855920 file format | file format | — | application/octet-stream | — | Use as new PL ↗ |
| 22DISK format Definition (with notes) Q105856300 file format | file format | — | application/octet-stream | — | Use as new PL ↗ |
| Ease Database Definition Q105856015 file format | file format | — | application/octet-stream | — | Use as new PL ↗ |
SWH-mined examples (0)
No archived examples for .def in our local mirror yet.