An artificial butter made by emulsifying a fatty oil with more or less milk and water; it was formerly made predominantly from animal fats, but now is made predominantly or exclusively from vegetable oils, sometimes mixed with animal fats. [
1913 Webster]
" Oleomargarine was wrongly so named, as it contains no margarin proper, but olein, palmitin, and stearin, a mixture of palmitin and stearin having formerly been called margarin by mistake."
[1913 Webster]