What is Advanced Training Institute?
1.
An organization that develops homeschooling curriculum, many times manifesting itself into a certain family lifestyle (see
Usually refered to as ATI (or ATIA, for old-timers), it has a connotation of strict rules, large families, and the infamous navy & white clothing.
"Did ya see that new family? There must be like a dozen kids and they were all wearing navy & white....I think they're ATI for sure."
See