You’ve probably heard seasoned project managers mention “waterfall methodology” countless times, maybe in comparison to Agile or when discussing traditional project approaches. But have you ever stopped to wonder why exactly it’s called “waterfall”? Did someone literally manage a project near a waterfall and decide to name a methodology after it? And more importantly for your growing project management vocabulary, what other names should you know for this approach when reading job descriptions, studying for your PMP certification, or discussing project strategies with stakeholders? If you’re an aspiring project manager trying to build your professional knowledge and communicate effectively in project management circles, understanding the origins of terminology and the various names used for this foundational methodology is more than trivia—it’s essential professional literacy. This comprehensive guide explores the fascinating story behind why waterfall got its name, reveals the multiple alternative names used across industries and contexts, and explains the subtle differences between these naming variations so you can speak the language of project management with confidence in any professional setting.
The Fascinating Origin Story: How Waterfall Got Its Name
Here’s a surprising fact that many project managers don’t know: the person who first documented the waterfall methodology never actually called it “waterfall.” In 1970, Dr. Winston W. Royce, a computer scientist working at the Lockheed Software Technology Center, published a groundbreaking paper describing his experience developing software for satellites. In this paper, Royce outlined a sequential approach to software development that moved through distinct phases—requirements, design, implementation, verification, and maintenance—with each phase completing before the next began. However, Royce never used the term “waterfall” in his original paper; instead, he referred to concepts like “the downstream value of documentation” and described a sequential development process.
So, where did the name “waterfall” actually come from? The term was coined six years later, in 1976, by Bell and Thayer when they reviewed Royce’s work and described his process diagram as a “waterfall of development activities.” The name stuck because of the powerful visual metaphor it created. When you plot the sequential phases of this methodology on a project timeline or Gantt chart, the cascading progression from one phase to the next resembles water flowing downward over the edge of a waterfall. Just as water in a waterfall cannot reverse its direction and flow back upward, work in the waterfall methodology flows steadily in one direction through each phase—requirements flow into design, design flows into implementation, implementation flows into testing, and so on. This one-directional, irreversible flow became the defining characteristic that gave the methodology its memorable name. For aspiring project managers studying examples of waterfall projects, understanding this visual metaphor helps clarify why going back to previous phases is discouraged and costly in this approach.
The Most Common Alternative Names You’ll Encounter
While “waterfall” is the most popular and widely recognized name, this project management methodology goes by several other names depending on the context, industry, or which aspect practitioners want to emphasize. The most common alternative is Linear Sequential Model or Sequential Development Model—these names emphasize the methodology’s defining characteristic: work progresses through a linear sequence of phases where each phase must be completed before the next begins. You’ll often see this terminology in academic contexts, software engineering textbooks, and formal project management documentation.
Another widely used alternative is Traditional SDLC (Software Development Life Cycle), particularly when discussing software and IT projects. The term “traditional” distinguishes waterfall from newer, more iterative approaches like Agile, Scrum, or DevOps. When someone refers to “traditional SDLC,” they’re almost always talking about waterfall methodology—the approach that dominated software development from the 1970s through the 1990s before Agile methodologies emerged. Similarly, you might hear the term Predictive Methodology or Predictive SDLC, which emphasizes the waterfall’s characteristic of requiring extensive upfront planning where project scope, schedule, and costs are predicted and fixed at the beginning. This contrasts with “adaptive” methodologies like Agile, where planning happens iteratively and adaptively throughout the project lifecycle.
In some contexts, particularly when distinguishing it from later variants and modifications, you’ll see Classical Waterfall Model—this term emerged once practitioners started creating modified versions and needed a way to refer to the original, pure waterfall approach. Other descriptive alternatives include the Linear Project Management Approach and the Sequential Project Plan, both emphasizing the straight-line progression through phases. Understanding why project managers need versatile knowledge helps you appreciate why recognizing all these naming variations matters in professional communication.
Variants With Their Own Specific Names
Beyond simple alternative names for the same methodology, several variants of the waterfall have evolved, each with its own specific designation that signals how it differs from the classical waterfall. The Sashimi Model (also called the Overlapping Waterfall Model) gets its name from the Japanese dish where slices of food overlap each other—in this variant, phases like requirements and design can overlap and occur simultaneously rather than waiting for complete sequential completion. This addresses one criticism of classical waterfall: that strict phase separation can slow down projects unnecessarily.
The V-Model (sometimes called the Verification and Validation Model) is a variation that emphasizes testing and quality assurance by pairing each development phase with a corresponding testing phase, creating a V-shaped diagram. In the V-Model, requirements correspond to acceptance testing, design corresponds to system testing, and implementation corresponds to unit testing—this ensures testing considerations are built into every development phase rather than saved for the end. The Iterative Waterfall Model introduces feedback loops within the traditional waterfall structure, allowing some iteration between adjacent phases while maintaining the overall sequential framework. This hybrid approach provides more flexibility than the classical waterfall while retaining its structural benefits.
Other specialized variants include the Incremental Waterfall Model (where the product is developed and delivered in increments rather than all at once), the Spiral Model (which adds risk assessment cycles to waterfall phases), and various Modified Waterfall or Hybrid Waterfall-Agile approaches that organizations create to suit their specific needs. When reading job descriptions or project methodologies, recognizing these variant names helps you understand exactly what approach an organization uses and how it differs from pure waterfall.
Why Understanding These Naming Variations Matters for Your Career
For aspiring project managers, understanding all these names isn’t just academic knowledge—it’s practical professional literacy that impacts your career in multiple ways. When studying for PMP certification or other project management credentials, exam questions may use any of these terms interchangeably, so recognizing them ensures you understand what’s being asked. When reading job descriptions, you might see requirements like “experience with traditional SDLC” or “knowledge of sequential project management”—knowing these refer to waterfall helps you assess whether you’re qualified and speak confidently in interviews.
In professional conversations with stakeholders, different industries and organizations have naming preferences: construction firms might say “sequential project planning,” IT departments might say “traditional SDLC,” defense contractors might say “predictive methodology,” and manufacturing teams might simply say “phased approach.” Being conversant in all these terms allows you to communicate effectively regardless of context and demonstrates your comprehensive project management knowledge. Additionally, when researching methodologies or reading project management literature, recognizing these various names helps you find relevant resources and understand that an article about “linear sequential models” contains information equally applicable to “waterfall methodology.” This naming literacy is part of developing the broad foundational knowledge that makes you a versatile, effective project manager capable of working across different industries and organizational contexts.
Your Path to Project Management Terminology Mastery
Understanding why the waterfall is called “waterfall” and knowing its various alternative names represents just one piece of the comprehensive project management knowledge you need to build a successful career. The visual metaphor of cascading water perfectly captures the methodology’s one-directional flow through sequential phases, while the multiple alternative names—linear sequential model, traditional SDLC, predictive methodology, classical waterfall—reflect different aspects and contexts where this approach appears. Recognizing variants like the Sashimi Model, V-Model, and Iterative Waterfall expands your professional vocabulary and helps you understand the nuanced ways organizations adapt foundational methodologies.
Ready to master not just terminology but the practical application of waterfall and other project management methodologies? Follow PMPwithRay on YouTube for clear explanations of project management concepts, terminology deep-dives, and practical guidance on when to use different approaches in real projects. For comprehensive training that builds both your theoretical knowledge and practical skills across waterfall, Agile, and hybrid methodologies, explore my Project Management Basics course and PMP Certification preparation materials on Udemy. Whether you’re preparing for certification exams, entering your first project management role, or advancing your career, mastering the language of project management positions you for long-term professional success.