An ecommerce online shop web application is a website that allows businesses or individuals to sell products or services online. It serves as a virtual storefront where customers can browse, select, and purchase items conveniently from their computers or mobile devices.

The web application typically consists of two main components:

1. Front-end: This is the user-facing part of the application that customers interact with. It includes the user interface (UI) elements such as product listings, search functionality, product details pages, shopping cart, and checkout process. The UI should be visually appealing, responsive, and intuitive, making it easy for customers to navigate and find products.

2. Back-end: The back-end is the behind-the-scenes part of the application that handles the business logic and database management. It manages tasks such as product inventory, order processing, payment gateways integration, user authentication, and user account management. The back-end also ensures the security and reliability of the application.

Key features and functionalities of an ecommerce online shop web application may include:

1. Product catalog: Displaying product listings with images, descriptions, and pricing information.

2. Search functionality: Allowing customers to search for products based on keywords, categories, or filters.

3. Shopping cart: Enabling customers to add items to their cart, update quantities, and proceed to checkout.

4. Payment integration: Integrating with payment gateways to facilitate secure and seamless online transactions.

5. Order management: Tracking and managing customer orders, including order confirmation, shipping, and delivery status.

6. User accounts: Allowing customers to create accounts, save their shipping and payment information, and view order history.

7. Reviews and ratings: Allowing customers to leave reviews and ratings for products, helping other shoppers make informed decisions.

8. Analytics and reporting: Providing insights into sales, customer behavior, and inventory management.

When building an ecommerce online shop web application, it's important to prioritize security, performance, and scalability to ensure a smooth and reliable shopping experience for your customers.