See also PaleoPaganism, NeoPaganism, What is Paganism

The term MesoPagan was first put forth by Isaac Bonewits in an attempt to categorize modern Paganism. According to Bonewits, MesoPagan religions are those that developed from PaleoPagan or native Pagan religions that were influenced by Monotheistic, Dualistic or Nontheistic philosophies. These include all synchretic religions including Christo-Paganism, many Afro-Diasporic faiths, such as Voudun, Santeria and Candomble, and Sikhism as well as many occult traditions including Thelema, Freemasonry, Rosicrucianism, Theosophy and Spiritualism and many modern Witchcraft traditions, including many Wiccan denominations. Also, some Satanic traditions could fall into this category.

The definition of MesoPaganism is nearly identical with that of syncretism, a word that enjoys common use in academic circles.

Reference

Defining Paganism: Paleo-, Meso-, and Neo- by Isaac Bonewits