1) The time when one takes their lunch break and/or eats their afternoon meal. 2) Any meal-time that is an unspecified time (e.g. not exactly at “noon”) set aside for the second meal of the day. 3) The time of day when one’s brain goes “out to lunch” and checks out for an extended break.
1. I’m so hungry...I got so busy today that lunch o’clock came and went and I didn’t eat.
2. Let’s go check out that new restaurant for lunch o’clock.
3. I started to draft that memo... then lunch o’clock hit, and my brain shut down for an hour.