The JavaScript Object Model (JSOM) refers to the way JavaScript organizes and manipulates objects within its environment. Objects in JavaScript are collections of key-value pairs that serve as the building blocks of the language, enabling structured data management and interaction. JSOM is foundational to understanding how JavaScript works, particularly in browser environments and JavaScript frameworks.

Core Features of JSOM:

1. Prototype-Based Inheritance: Objects in JavaScript inherit properties and methods through a prototype chain. This enables code reuse and the creation of complex hierarchies without traditional class-based structures.
2. Dynamic Object Creation: Objects can be created dynamically using object literals ({}), constructors (new), or classes (introduced in ES6 for syntactic sugar).
3. Manipulation of Properties: JSOM allows adding, modifying, and deleting object properties at runtime.
4. Encapsulation: Through closures and ES6 features like private fields, JSOM supports encapsulating data and logic.

JSOM is integral to working with APIs like the Document Object Model (DOM), where objects represent elements of a web page, and the Fetch API, which relies on objects for configuration and responses. It is also central to JavaScript frameworks and libraries, such as React and Vue.js, which use object models to manage state and rendering.

Understanding JSOM is critical for developers building interactive, data-driven web applications or working with modern JavaScript features like destructuring, spread/rest operators, and object-oriented design patterns.