TV series example of the word

The Big Bang Theory Season 1, Episode 10
Yeah, for a noble purpose.

Game of Thrones Season 4, Episode 9
They lose their purpose. They go back to fighting each other.

Game of Thrones Season 7, Episode 3
Cersei believes my sole purpose in life

Game of Thrones Season 1, Episode 4
but I don't quite see the purpose of this.

Game of Thrones Season 3, Episode 7
What's the purpose of an arm with no hand?