"A deliverable-oriented grouping of project elements that organizes and defines the total work scope of the project. Each descending level represents an increasingly detailed definition of the project work." (Timothy J Kloppenborg et al, "Project Leadership", 2003)
"A method for breaking your project into component tasks and organizing your management structure." (Michael S Dobson, "The Juggler's Guide to Managing Multiple Projects", 2003)
"An arrangement of work elements and their relationship to each other and to the end product." (Sandy Shrum et al, "CMMI®: Guidelines for Process Integration and Product Improvement", 2003)
"The process of dividing a project into manageable tasks and sequencing them to ensure a logical flow between tasks." (Lynne Hambleton, "Treasure Chest of Six Sigma Growth Methods, Tools, and Best Practices", 2007)
"A structured list of all activities and tasks required to complete a project." (Steven Haines, "The Product Manager's Desk Reference", 2008)
"A work breakdown structure (WBS) is an arrangement of project elements consisting of deliverables or project phases. It structures and defines the overall project content and scope." (Lars Dittmann et al, "Automotive SPICE in Practice", 2008)
"A deliverable-oriented hierarchical decomposition of the work to be executed by the project team to accomplish the project objectives and create the required deliverables. It organizes and defines the total scope of the project." (Project Management Institute, "Practice Standard for Project Estimating", 2010)
"A hierarchical diagram showing work broken down into smaller packages to facilitate estimating work and costs, and tracking progress." (Bonnie Biafore, "Successful Project Management: Applying Best Practices and Real-World Techniques with Microsoft® Project", 2011)
"An arrangement of work elements and their relationship to each other and to the end product [CMMI]." (International Qualifications Board for Business Analysis, "Standard glossary of terms used in Software Engineering", 2011)
"Formal tool that breaks the project (the work) down into a structure – allowing a firm inventory of tasks, in a logical hierarchy." (Mike Clayton, "Brilliant Project Leader", 2012)
"The framework in which the project goal is deconstructed into manageable, task-sized details called work packages to identify all work to be done to complete the project." (Bonnie Biafore & Teresa Stover, "Your Project Management Coach: Best Practices for Managing Projects in the Real World", 2012)
"A hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables." (For Dummies, "PMP Certification All-in-One For Dummies, 2nd Ed.", 2013)
"A task-oriented detailed breakdown of activities which organizes, defines, and graphically displays the total work to be accomplished in order to achieve the final objectives of a project. WBS breaks down the project into progressively detailed levels. Each descending level represents an increasingly detailed definition of a project component. In CPM scheduling, the components at the lowest WBS level are used as activities to build the project schedule." (Christopher Carson et al, "CPM Scheduling for Construction: Best Practices and Guidelines", 2014)
"The planned work to take place in a project hierarchically decomposed into work packages of 80 hours or less." (Cate McCoy & James L Haner, "CAPM Certified Associate in Project Management Practice Exams", 2018)
"A hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables." (Project Management Institute, "Practice Standard for Scheduling 3rd Ed.", 2019)
"An arrangement of work elements and their relationship to each other and to the end product." (CMMI)
