RPN
n.— «A key direct marketing initiative for the postal service this year is repositionable notes, also known as “yellow stickies.” A test began this month allowing for the use of RPNs on some types of mail for which they are currently prohibited—but a fee also was instituted.» —“Deliver: Carriers, Suppliers Offer New Initiatives” by Melissa Campanelli DM News Apr. 4, 2005. (source: Double-Tongued Dictionary)
Further reading
Cat hair may be something you brush off, but cat hair is also a slang term that means “money.” In the same way, cat beer isn’t alcoholic — some people use cat beer as a joking term for “milk.” And imagine walking on a...
There are eight major planets, but more than a million minor ones, including asteroids. If you discover one, you get the honor of naming it. The Dictionary of Minor Planet Names includes minor planets named for rock bands, jazz musicians, poets, and...