Forward vs Reverse proxy

Unlike a forward proxy, which is an intermediary for its associated clients to contact any server, a reverse proxy is an intermediary for its associated servers to be contacted by any client. This means that a forward proxy is not bound to any specific server.
--Wikipedia

Reverse cache in reverse proxy replicates query results to reduce db server loads. This means that a reverse proxy is bound to any specific server. Example is AWS Cloudfront CDN.

Nginx is http server application and reverse proxy.

Redis is in memory data store and can be used to implement server side cache and can be used with nginx.