In JavaScript, an object is a non-primitive data type that allows you to store multiple collections of data. An object is a collection of properties, and a property is an association between a name (or key) and a value. Properties can be added, modified, or deleted from an object. In JavaScript, objects can be compared to objects in real life, such as a cup that has properties like color, design, weight, and material it is made of.

JavaScript objects are containers for named values called properties. The values are written as name:value pairs, separated by a colon. You can define and create a JavaScript object with an object literal, which is a comma-separated list of name-value pairs inside curly braces.

To access object properties, you can use either dot notation or bracket notation. Dot notation is used when you know the name of the property you want to access, while bracket notation is used when the name of the property is stored in a variable or when the name contains special characters.

In summary, an object in JavaScript is a collection of properties that define its characteristics. It is a non-primitive data type that allows you to store multiple collections of data. You can add, modify, or delete properties from an object, and you can access object properties using dot notation or bracket notation.