The story
- Proto-Indo-European*sem-
- Proto-Indo-European*sēmi
- Latinsēmi-
- Englishsemi-
- Latinvegetābilis
- Old Frenchvegetable
- Middle Englishvegetable
- Englishvegetable
- Englishvegetarian
- English todaysemivegetarian
From semi- + vegetarian.
Etymology from Wiktionary, CC BY-SA 4.0.