Etymology
1. Etymology tree
2. Proto-Indo-European *(s)krebʰ-der.?
3. Latin scrōfa
4. Old French escrouebor.
5. ▲
6. Old French escruveinflu.
7. Middle English scrue
8. English screw
9. From Middle English screw, scrue (“screw”); apparently, despite the difference in meaning, from Old French escroue (“nut, cylindrical socket, screwhole”), from Latin scrōfa (“female pig”) through comparison with the corkscrew shape of a pig's penis. There is also the Old French escruve (“screw”), from Old Dutch *scrūva ("screw"; whence Middle Dutch schruyve (“screw”)), which probably influenced or conflated with the aforementioned, resulting in the Middle English word.
10. more on the etymology of screw
11. Old French escroue (whence Medieval Latin scrofa (“nut, screwhole”)), is believed to be an adaptation of Latin scrōfa (“sow, female pig”); but this development is not found in other Romance languages. (For change in meaning, compare also Spanish puerca, Portuguese porca, both ‘sow; screw nut’, and is based on the fact that a boar's penis has a screw-like tip, making the sow's vulva equivalent to a screw nut by analogy).
12. Old Dutch *scrūva possibly derives from Proto-Germanic *skrūbō (“screw”), from *skru- (“to cut”), from Proto-Indo-European *(s)keru-, *(s)ker- (“to cut”), and is related to German Schraube (“screw”), Low German schruve, schruwe (“screw”), Dutch schroef (“screw”), West Frisian skroef (“screw”), Danish skrue (“screw”), Swedish skruv (“screw, peg”), Icelandic skrúfa (“screw”).
13. Compare also Occitan escrofa (“screw nut”), Calabrese scrufina (“screw nut”), which may be borrowings of the Old French word, or parallel developments. See: Danish '
skrue', Icelandic '
skrúfa'.