Milk pox and Variola major

Milk pox noun - A mild form of smallpox caused by a less virulent form of the virus.

Variola major and milk pox are semantically related. In some cases you can use "Variola major" instead a noun phrase "Milk pox".

Variola major noun - A highly contagious viral disease characterized by fever and weakness and skin eruption with pustules that form scabs that slough off leaving scars.

Milk pox and variola major are semantically related. Sometimes you can replace phrase "Milk pox" with "Variola major", this phrases are similar.