What it sounds like: A duck that's been wounded.
What it means in conversation: An elected public official who has been either defeated in a new election or whose term cannot be renewed, but who has a short period of time left in office during which he can still perform certain duties, though with somewhat diminished powers.
The United States recently had a lame duck session in congress and the senate between the elections and the swearing in process. Since the elections are in November, the officials who are being replaced still have to serve out their terms until January.
Lame duck sessions can be interesting because the officials who are leaving office at the end of the term don't have to worry about their re-election chances. Since they know they will be out of office, they can do things they wouldn't have done before. If there is going to be a sizable shift from one party to the other in January, the party that is losing the majority may try to push through as much legislation as possible before they have to leave office.
