Who uses it: Roadbuilders and drivers
What it means: The concrete dividers between highway lanes, specifically the ones that have curved lower halves.
How you can use it: Watch out, Congressman Kennedy!
Okay, it's not funny; but it is a weird coincidence that I'd already chosen this for today's (Thursday's) term of art, and then saw the news item about Rep. Patrick Kennedy (D-RI) crashing into a barrier outside the Capitol.
And in case you were wondering, they're called Jersey barriers because they really were developed in New Jersey. The very first concrete highway dividers were used in California in the 1940s, but New Jersey developed the curbed design for their median barriers in the 1960s. California borrowed New Jersey's design, and they're now used nationwide.
Other than that, I want to say only that it is a long, long, looooong way from Washington, D.C. to Gardiner, Maine. Good night.