what's this, etc. in aid of?

What's (something) in aid of?

What is the reason for or purpose of something? Someone told me they just called an all-hands meeting for this afternoon. What is that in aid of?
See also: aid

what’s (all) ˈthis, etc. in aid of?

(British English, spoken) what is the purpose or cause of something?: What’s all this crying in aid of?
See also: aid