The Waterfall Model is a sequential software development process in which progress flows steadily downwards (like a waterfall) through a series of distinct phases.
The standard phases of the Waterfall Model, in order, are:
1. Requirement Gathering and Analysis: Understanding and documenting what is needed.
2. System Design: Defining the architecture, components, modules, interfaces, and data for the system.
3. Implementation (Coding): Writing the actual source code.
4. Testing (Verification): Finding and fixing defects in the code.
5. Deployment: Releasing the software to the users.
6. Maintenance: Making modifications to the software after its release.
Therefore, the second phase of the waterfall model is Design.