What is a pattern

"A pattern is a proven solution to a problem in a context."

It solves a problem: Patterns capture solutions, not just abstract principles or strategies.

It is a proven concept: Patterns capture solutions with a track record, not theories or speculation.

The solution isn't obvious: Many problem-solving techniques (such as software design paradigms or methods) try to derive solutions from first principles. The best patterns generate a solution to a problem indirectly--a necessary approach for the most difficult problems of design.

It describes a relationship: Patterns don't just describe modules, but describe deeper system structures and mechanisms.

The pattern has a significant human component (minimize human intervention). All software serves human comfort or quality of life; the best patterns explicitly appeal to aesthetics and utility