The time when you get off work on Friday night and head over to the bar or to a friend's house.
Finally beer o'clock! I'm heading off the bar!
No matter what the actual time it is, it's time to drink.
Guy 1: What time is it? It feels like too late for another drink...
Guy 2: Glad you asked. It's Beer o'clock!
Guy 1: He got me! This guy... Alright, two more beers lovely bartender!
Any time of the day when happy hour starts in the office. Can be any time of the day.
Oh shit, it's beer o'clock. Time to start drinking!
Hey, it's beer o'clock! What is everyone still doing in the office?
Another way of saying "time for a drink"
Can be used at finishing time of work, at the end of a sporting event or any time that "time for a drink" would be mist appropriate
at work day's end
"righto boys, beer o'clock"