Just when you thought it was getting safe, some economists are predicting a "W"-shaped recovery. What's that? It means things could get worse again before they get better for the long term.

W's and dead cats. The "W" is a reference to the down-up-down-up shape of the line on a graph that plots a volatile economy over time. Forbes' Investopedia provides definitions of the myriad of terms bandied by investors and economists. It compares a "W" recovery with a "V," a "U," and a dreaded "L." Under related terms, we discover comparable expressions, such as the "double-dip recession" and the vivid "dead cat bounce."

http://go.philly.com/w1

A gloomy U. Instead of a W, "a gloomy U with a long, flat bottom of weak growth is the likeliest shape of the next few years," says the stalwart Economist. The "W" doesn't turn up in the site's glossary of economic terms, although "wage drift," and "winner-takes-all markets" are among the offerings. The British magazine's site covers economic and political news from a global perspective - evidenced by its recently added, and mind-boggling, Global Debt Clock.

http://go.philly.com/w2

"Sesame Street"? With letters from the alphabet being paraded in so much talk about the recovery, says this posting at EconomyWatch.com, "the discussion sounds more like an episode of Sesame Street with each passing day." The posting is largely about recent arguments by economist Nouriel Roubini - who predicted the recession and is sometimes referred to as "Dr. Doom" - that "the likelihood of a 'W' is rising."

http://go.philly.com/w3

X marks the recovery. Not to be out-lettered, University of Maryland business professor Peter Morici argues in this Bloomberg News video that the "X" is the shape of the recovery. What that seems to mean is that while some economic indicators may be on the rise, others - such as employment - will continue to look worse. "For ordinary working people, there won't be much of a recovery," Morici said. We found the video on YouTube.

http://go.philly.com/w4

Contact staff writer Reid Kanaley at 215-854-5114 or rkanaley@phillynews.com.