In spring 2001 I had written Apache mod_accel that is enhanced replacementof mod_proxy. But it was clear that Apache has low scalability. I had read http://kegel.com/c10k.html, had investigated existent servershttpd, boa, etc. and had decided that I need something like these servers, but with SSI, proxy, and cache support. Also it should has flexible configuration like Apache and supports online upgrade and quick log rotation.
The base for name was NG letters those sounds like en-gee in English (I at least I think so :). X is simply fine letter. But ngx was already used many times. There were some variants – ngnx, nginx and nginex. nginx seemed the better for me and I had look it in Google and found the only quote symbol.
via history of Nginx.