What Exactly Is a 'Limited War?'

The US often proclaims the war they are launching to be limited in scope and time. Yet often these wars drag on as troops get bogged down, focus or aims of war change, and the people who welcomed US troops as liberators or defenders, turn on them as occupiers. Days turn into weeks, weeks to months and wham suddenly all the TV channels are doing 10 year anniversary pieces. Just over one week into the Libya war and there is already talk of weeks, not days. NATO predicts 3 months while the Pentagon thinks it will take significantly longer. So will this become an odyssey of death and destruction.