in aid of

in aid of

1. (UK, informal) for the sake of, for (usually placed at the end of a question when quizzing a person about why they have done something)

   - What's that coaster in aid of?

   - This table gets stained by cups very easily.

• what for

• “what s sth in aid of”, in Cambridge English Dictionary, Cambridge, Cambridgeshire: Cambridge University Press, 1999–present.