If something or someone is popularly known as something, most people call them that, although it is not their official name or title.
commonly
the Mesozoic era, more popularly known as the age of dinosaurs.
中生代,俗称恐龙时代。
an infection popularly called mad cow disease.
俗称疯牛病的一种传染病。
If something is popularly believed or supposed to be the case, most people believe or suppose it to be the case, although it may not be true.
Schizophrenia is not a 'split mind' as is popularly believed.
精神分裂症并不是普遍认为的“分裂了的精神”。
A popularly elected leader or government has been elected by a majority of the people in a country.
Walesa was Poland's first popularly elected president.
瓦文萨是波兰的第一位普选总统。