I am thinking of doing something similar to the next:

(in browser address bar, without any forward slashes)

fa234

And also have this time to http://localhost/FA234

During my httpd.conf I made use of

Redirect permanent /fa234 http://localhost/FA234

but this assumes /fa234 within the address bar is preceded by localhost.

It is possible to method to configure httpd.conf so an easy word (without slashes) indicates a website?

Thanks

No since this is not really a job for apache. Should you enter fa234 your browser tries to find information about the ip adress with this hostname. If it's only local and you won't want to use DNS you are able to modify your hosts file and enter fa234 localhost to ensure that it will likely be rerouted to localhost. But as stated above no chance by setting up apache