What does "Have a yarn" mean?
It means having a relaxed chat, often with a story or two along the way. A yarn can also mean a story, especially one told for entertainment.
The saying in a sentence
The saying
Have a yarn
Example
Come in and have a yarn.
When you use it
Use it when inviting someone to sit down for a friendly chat or catch up over a cuppa.
When you do not
It is less suited to a formal meeting or an urgent conversation. It suggests you have time to talk without rushing.