What is the source for preferred spelling in APA Style®?
This page reflects guidance from the sixth edition of the Publication Manual.
For the most current guidelines, see the Publication Manual of the American Psychological Association (7th ed.) and our Style and Grammar Guidelines page for the seventh edition.
The APA Publication Manual recommends Merriam-Webster's Collegiate Dictionary (2005) as the standard spelling reference for APA journals and books for nonpsychological terms; spelling of psychological terms should conform to the APA Dictionary of Psychology (VandenBos, 2007).
If a word is not in Webster's Collegiate, try consulting the more comprehensive Webster's Third New International Dictionary (2002).
If the dictionary gives a choice, use the first spelling listed; for example, use aging and canceled rather than ageing and cancelled.
(adapted from the sixth edition of the APA Publication Manual, © 2010)