Acronym: A word created from the first letters of other words. 

For example:

• NASA – National Aeronautics and Space Administration.
• BOOK – Box Of Organized Knowledge
• CLASS – Come Late And Start Sleeping
• PHD – Please Hire.  Desperate.

From Greek ἄκρον (height, summit, peak), and and ὄνομα (name).

Need help with an acronym?  Here you go: http://www.acronymfinder.com/