In day to day usage (by which I mean non-scientifically specific), what would you say is the shortest period of time an era could be?
Definitions of the word state:
...a long and distinct period of history with a particular feature or characteristic.
The thought occurred when I came across a text which said "from the World War II era". To me this seems a inaccurate use of the word (being ~6 years), but I can't find anything to backup my assertion that it needs to be longer than this.