The Postal Service has a healthy list of acronyms and abbreviations. You might say the organization has its own "alphabet soup." Ingredients range from ADC to APO, DMM and EAP, FSS, GMF, IMb, OTR, PRC to ZIP and hundreds more. *(How many acronyms/ abbreviations did you identify? Answers at end of this story).
For the record, acronyms and abbreviations are not the same. Organizations favor acronyms because they take letters from a multi-word term to form single, easy-to-remember word. For example, Employee and Labor Relations Manual becomes “ELM.” Abbreviations are a shortened form of a word or phrase.
Why use acronyms and abbreviations?
The simple answer is they work. Agencies with a penchant for acronyms and abbreviations figured out years ago that people prefer familiar and easy-to-pronounce names over long names that are hard to remember.
That was the reason behind the acronym ZIP. How many customers want to hear about a “Zone Improvement Plan?” The Post Office Department did studies nearly 50 years ago and found the best way to increase the speed of mail sorting and delivery was to abandon its 2-digit zone system in favor of a 5-digit system. But they also realized the additional three digits might make addressing letters seem more complicated. After all, it’s much easier to remember 2-digit codes for only 100 areas than it is to remember 5-digit codes for almost every city and town in America. The decision to use the acronym ZIP — implying speed — helped customers accept the longer number because they could understand not only what was being planned (a new national zone system), but also why (make mail deliveries faster).
Postal acronyms and abbreviations may be practical, but by sheer number it’s difficult to know them all. Luckily, there’s help. Publication 32, Glossary of Postal Terms, defines postal words. First published in 1974, the 140-page publication has been the main source to find the most common postal terms. You can find the online version on usps.com.
*Answers (ADC, area distribution center; APO, Army Post Office; DMM, Domestic Mail Manual; EAP, Employee Assistance Program; FSS, flats sequencing system; GMF, general mail facility; IMb, Intelligent Mail barcode; OTR, over-the-road container; PRC, Postal Regulatory Commission; ZIP, Zone Improvement Plan).
Source: liteblue.usps.gov "Behind the Blue"