I have seen people refer to the "Erling brick" or "headlight brick" on LEGO forums. What kind of brick are they talking about?
I definitely know them as the headlight brick, and they look like this:
HoMa's world of bricks has a nice page dedicated to this brick!
LEGO's Pick a Brick lists this as an "Angular Brick 1x1", Design ID 4070 (equivalent to the piece/part id).
The Erling Brick: named by the LEGO Designer Erling Dideriksen, who invented this element in 1979.