Sentence:  The name "Bash" is an acronym which stands for "Bourne-again shell", itself a pun on the name of the "Bourne shell", an earlier Unix <WSD>shell</WSD> designed by Stephen Bourne, and the Christian concept of being "born again". 
Meaning of the word marked with <WSD> tags:  An operating system software user interface, whose primary purpose is to launch other programs and control their interactions; the user's command interpreter.