Linked from
The 24 pages that link to Mayonnaise, each with the reason it gives.
Vegetable oilBroader topic: Vegetable oil supplies most of its volume and characteristic texture.
EggBroader topic: Yolk emulsifiers help keep its oil droplets dispersed.
EmulsifierBroader topic: Egg-yolk components help stabilize its dense oil-in-water structure.
CondimentBroader topic: It is served as a condiment and forms the base of many dressings and dips.
Eggs as foodBroader topic: Yolk helps stabilize the oil-and-water mixture that defines mayonnaise.