- a day in which not much happens, so it feels like it is taking very long to pass
- a day in which less than expected has been done
- not much business has been done
- The shop did not make a lot of money today, we had a slow day.
- Very few people came into the restaurant today, the servers did not even have to set up the tables at the back, we had a slow day.
- Today is Saturday, we are going to stay home and watch television, we are not going to leave the house at all, we are having a slow day.
- I cannot believe that it is only 12 o'clock, it feels like we have been here for hours, it really has been a slow day.
- Waiting for something exciting to happen, like going to a concert makes it feel like the day is taking longer than usual to pass, it is a slow day.
Though no definite origin of the idiom could be found, it can, however, be compared to saying "a slow as molasses day" which originates from a tank of almost 10 million litres of molasses that spilled from a tanker in Boston in 1919. Molasses is a very thick substance and moves very slowly.