a bad dream when you sleep during daytime. opposite of nightmare.

A bad dream that is so horrific. It came in your mind while you were sleeping in the day... Although it should have occurred at night. It obviously a nightmare that happened in the day.

it is having a nightmare during the day while one is awake. usually leads to the person to sleep in order to escape the horror that was presented during the incident. there could be multiple incidents in one day of extreme horror. it simpler words it is like having a bad day, yet so much worst that it leads you to hope the next day will just come already.

(Day-mare)
A scary day dream.

A vivid, unpleasant mental image (as in a nightmare) conjured in broad daylight, such as an impending crash, or a thought of a loved one in distress, which can cause a strong emotional response such as fear or horror.

A good dream while sleeping. As opposed to nightmare.