Term: 3 day shadow
Example: jim: hey bob, you've gotta nice mustache, what'd you grow that today?  bob: lol, oh no, its just my 3 day shadow
Definition: much like 5 o'clock shadow, but for those who have just started shaving, and their beard/mustache/sideburns have not become thick enough to develop by 5 o'clock, but 3 days later