504 refers to Section 504 of the Rehabilitation Act that precedeed the Americans with Disabilities Act and provides accommodations in educational and public settings. "504 plans" are typically found in K-12 schools as a way to outline the needed accommodations for students with disabilities. More information can be found here: https://www.wrightslaw.com/info/sec504.index.htm
Other glossaries and definitions of terms are available at:
Wisconsin’s Department of Children and Families has a list of Acronyms and Definitions for Early Childhood here.
A list of insurance-related definitions can be found here.
Have suggestions? Email us at firstname.lastname@example.org