Kotlin has an object keyword, which combines both declaring a class and creating an instance of it in one action. It can be used in three different situations and has three different meanings. Let's take a look at all of them:

• Object declaration: Defines a singleton class.
• Companion object: Defines a nested class that can hold members related to the outer containing class. These members can't require an instance of the outer class.
• Object expression: Creates an instance of the object on the fly, the same as Java's anonymous inner classes.