What is a "low church?" I was raised Baptist...
"... know that we don’t deify Mary."
... and I know you don't.
High Church applies to denominations such as Catholicism, Episcopalianism, Lutheranism, the Orthodox church, etc.
Low Church denominations would include most Baptist incarnations, Pentecostalism, the snake handlers, etc. By the definition of what an evangelical church truly is, and how evangelicals worship, as opposed to how say, the Catholic worships, is what marks the Evangelical as belonging to a low church religion and the Episcopalian as belonging to a high church religion.
It’s more of a word used in the South, because in general, there is a correlation between religious preference and social status. Outside of actual preachers, in general, members of low church denominations tend to be lower on the social heirarchy than members of high church denominations. Of the two major Protestant faiths in the South, numerically speaking, the Baptists have the numbers, but, in general, Methodists tend to have more money and more affluence, and, it is also true that Baptists who are in the Southern upper class tend to often reject certain elements of Baptist social teaching (such as those regarding alcohol)
It also has a meaning theologically speaking, but I’m not a theologian so I can’t go into that.