What's the difference between i.e. and e.g.?
1706, "conversion to secular purposes," in reference to Church property; see secularize + -ation. General use by 1863.
1610s, of property, offices, etc., from secular + -ize. From 1711 as "to become worldly;" from 1846 of education, social institutions, etc. Related: Secularized; secularizing.