Oracle Version Numbers

Something that always comes up when discussing Oracle versions is that I am not always sure which number is the Major Database Release and which is the Database Maintenance Release. In the Oracle documentation, the numbers are clearly described:

Oracle Release Number Format

12.1.0.1.0
 ┬ ┬ ┬ ┬ ┬
 │ │ │ │ └───── Platform-Specific Release Number
 │ │ │ └────────── Component-Specific Release Number
 │ │ └─────────────── Fusion Middleware Release Number
 │ └──────────────────── Database Maintenance Release Number
 └───────────────────────── Major Database Release Number

Whereas the different numbers mean the following:

Major Database Release Number
The first numeral is the most general identifier. It represents a major new version of the software that contains significant new functionality.

Database Maintenance Release Number
The second numeral represents a maintenance release level. Some new features may also be included.

Fusion Middleware Release Number
The third numeral reflects the release level of Oracle Fusion Middleware.

Component-Specific Release Number
The fourth numeral identifies a release level specific to a component. Different components can have different numbers in this position depending upon, for example, component patch sets or interim releases.

Platform-Specific Release Number
The fifth numeral identifies a platform-specific release. Usually this is a patch set. When different platforms require the equivalent patch set, this numeral will be the same across the affected platforms.