Defining trait is that they have characteristics of Gen X and so called Gen Y, yet do not really feel like they are part of either. Also remember the Pre-Information age society, Cold War, and the arrival of the Gulf War.
Statisticians usually start at '81 and atop at '85. Strongest alienation seems to be between '81 -'83. Is not regulated to years as this 'in limbo' feeling can go back as far as the late '70s. Seemingly making the original end dates of Gen X as the most accurate.
They might even take offense being called Cold Y and make up their own name.