Late Latin companio: com (with) plus panis (bread). A companion was the person you broke bread with; the same root gives company. Shared food created binding obligation across many cultures.
Assessment: Fully documented.
Interesting claims
Words preserve ancient hospitality law
Symbolic readings point to companion, lord (loaf-ward), and lady (loaf-kneader) as proof English encodes a lost sacred economy of bread.
Assessment: The individual etymologies are real. The unified theory built on them is speculation, though compelling.
Stories
The bread oath
The story: to break bread with someone was to bind yourself to them, and armies, guilds, and households ran on shared loaves. A companion was not a friend but a witness to your meals, and meals were security clearances.
Assessment: The word's anatomy is documented; the oath is the story humans keep telling about food, from the Last Supper to the business lunch. Eating together remains the cheapest trust protocol ever invented.
Sources and further reading
OED, companion, from Late Latin companio, one who shares bread (panis)
Worth asking
If friendship is defined by bread, what defines it in an age that eats alone?