What is bullying? A theoretical redefinition Anthony A. Volk a, *, Andrew V. Dane b , Zopito A. Marini a a Department of Child and Youth Studies, Brock University, St Catharines, Ontario, Canada b Andrew Dane, Department of Psychology, Brock University, St Catharines, Ontario, Canada A R T I C L E I N FO Article history: Received 2 August 2013 Revised 24 September 2014 Available online 14 October 2014 Keywords: Bullying Bullying definition Goal-directedness Power imbalance Harm Theory A B ST R AC T Bullying is a complex and heterogeneous phenomenon that direct- ly affects hundreds of millions of people each year. The importance of bullying has led to research in the last two decades that has pro- duced hundreds, if not thousands, of papers on the topic. In large part this research was stimulated by a definition provided by Olweus in 1993. That definition has proven to be tremendously useful as a starting point for research, but it was created in the absence of recent empirical and theoretical evidence. We propose an updated defi- nition that is explicitly grounded in a unifying theory that encompasses ecological and evolutionary contexts: “bullying is ag- gressive goal-directed behavior that harms another individual within the context of a power imbalance”. We follow this definition with an examination of the theoretical and empirical support for each of its three elements (goal-directedness, power imbalance, and harm). We suggest that bullying measures should be based on assess- ments of these three elements of bullying. Our redefinition also emphasizes the importance of considering and altering the cost– benefit analysis of bullying as a cornerstone for successful interventions. Finally we address several specific potential chal- lenges to the definition. © 2014 Elsevier Inc. All rights reserved. Introduction Bullying is a centuries old term that, according to Merriam-Webster (2013), was first coined from German in 1538 and means one of three things: a fine chap, a hired ruffian, or a blustering brow- * Corresponding author. Department of Child and Youth Studies, Brock University, St Catharines, Ontario, Canada L2S 3A1. Fax: (905) 641-2509. E-mail address: tvolk@brocku.ca (A.A. Volk). http://dx.doi.org/10.1016/j.dr.2014.09.001 0273-2297/© 2014 Elsevier Inc. All rights reserved. Developmental Review 34 (2014) 327–343 Contents lists available at ScienceDirect Developmental Review journal homepage: www.elsevier.com/locate/dr