Longman Dictionary of Contemporary English - aid

~1 S2 W2 n 1 help, such as money or food, given by an organization to a country or to people who are in a difficult situation  (Aid is not getting through to the refugees.) in ~ of (=in order to help)  (We're collecting money in aid of cancer research.) legal ~ (=free legal services) 2 help or advice given to someone who needs it come/go to sb's ~ (=help someone)  (I didn't speak any French, but a nice man came to my aid and told me where to go.) 3 something such as a machine or tool that helps someone do something  (A video is a useful aid in the classroom.) with the ~ of  (He was able to prove the existence of the supergun with the aid of a photograph.) 4 what's this in ~ of? BrE spoken used to ask what something is used for or why someone is doing something  (What's this meeting tomorrow in aid of, then?) 5 an American spelling of aide  (- see also first aid) ~2 v formal 1 to help someone or something by making their situation or what they are doing easier  (an index to aid the reader) ~ sb in/with sth  (The local community aided us in our investigation. help1 (USAGE)) 2 ~ and abet law to help someone do something illegal