wall wart

( n.)

   A  small power-supply brick with integral male plug, designed to plug
   directly  into  a wall outlet; called a `wart' because when installed
   on  a  power strip it tends to block up at least one more socket than
   it  uses. These are frequently associated with modems and other small
   electronic  devices  which  would become unacceptably bulky or hot if
   they  had  power  supplies  on board (there are other reasons as well
   having to do with the cost of UL certification).

[glossary]