The PTA is a national organization and only official members can call themselves PTAs. There are many independent parent groups that go by a variety of names that we, in general terms, refer to as PTOs. You'll see other PTLs among our community, along with PCCs (Parent Communication Councils) HSAs (Home School Associations) and many, many more.
Thought I would include a link to our article on the differences between PTAs and PTOs: www.ptotoday.com/pto-today-articles/arti...whats-the-difference
Hope this helps!