Dic: for (as a meaning of purpose/function, reason/cause, in order to obtain sth)

8 △ used to show purpose or function

• a machine for slicing bread
• Let's go for a walk.
• Are you learning English for pleasure or for your work?
• What did you do that for (= Why did you do that)?

9 △ used to show a reason or cause

• The town is famous for its cathedral.
• She gave me a watch for my birthday.
• He got an award for bravery.
• I couldn't speak for laughing.
• He didn't answer for fear of hurting her.

10 △ in order to obtain something

• He came to me for advice.
• For more information, call this number.
• There were over fifty applicants for the job.

.... OALD