In software development, there are two key levels of design: high-level design and low-level design. These two levels of design help software developers break down complex software problems into smaller, more manageable pieces.

High-level design refers to the overall architecture of a software system. It is the big-picture view of the system, which includes the major components and how they fit together. The goal of high-level design is to define the structure of the software system, as well as the interactions between its various components.

For example, let's say we are designing a web application for an online store. The high-level design of the application might include components such as a front-end user interface, a back-end database for storing product information and customer data, and a payment processing system. The high-level design would describe how these components interact with each other, and how they work together to provide the desired functionality.

Low-level design, on the other hand, is the detailed design of individual components or modules. It involves breaking down the high-level design into smaller, more specific pieces, and defining how each of these pieces should be implemented.

For example, if we are designing the front-end user interface for our online store application, the low-level design might include defining the layout of the web page, the specific user interface components (such as buttons and forms) that will be used, and the JavaScript code that will be used to handle user interactions. The low-level design would also specify how the front-end user interface will interact with the backend database and payment processing system.

In summary, high-level design and low-level design are two important levels of design in software development. High-level design defines the overall architecture of a software system, while low-level design defines the detailed design of individual components or modules. By breaking down complex software problems into smaller, more manageable pieces, developers can create software systems that are easier to understand, maintain, and scale.