A back-end database is a database that is accessed by users indirectly through an external application rather than by application programming stored within the database itself or by low level manipulation of the data (e.g. through SQL commands).
A back-end database stores data but does not include end-user application elements such as stored queries, forms, macros or reports. Source: CoolInterview.com
There are two way of replying to customers:one is by call and second is by mail and etc.When our work is only related to computer not by calls.That work comes in Backed or non voice. Source: CoolInterview.com
Backend now a days used in to terms,first in case of database ex sql oracle etc and the other is where you are doing data handling or data storage not by any command means simply entering data in table for small business