Panacea
/ˌpæn.əˈsiː.ə/ noun easyA panacea is a single fix that is believed, often naively, to solve every kind of problem at once.
The mayor promised the new stadium would be a panacea for the city's economic troubles, but few economists agreed.
Memory Trick
'Pan-' means all, as in Pan-American, and '-acea' echoes cure - a panacea is a cure-all for everything.