Other forms: daydreaming, daydreams, daydreamed
A daydream is the small film that starts playing in your head while you are wide awake. You are meant to be listening in a meeting, and instead you are on a beach, or spending money you have not won, or saying the clever thing you should have said last week.
It works as a verb as well: to daydream about a different job, to daydream your way through a lesson. A person who does it a lot is a daydreamer, and that word carries a light criticism — someone who plans beautifully and finishes nothing. Keep it apart from a dream, which happens when you are asleep and which you do not choose, and from a fantasy, which can be darker or wilder. A daydream is comfortable, pleasant, and yours.
1noundaydreamA pleasant series of thoughts you have while awake, which takes your attention away from what is around you.
“She was deep in a daydream when her name was called.”
2verbdriftTo let your thoughts drift pleasantly while you are awake.
“He spent the whole geography lesson daydreaming about the holidays.”
Too few real examples of this word to estimate which sense is commonest.
daydream is a kind of thought.
Daydream is exactly what it looks like: day plus dream, a dream had in daylight. The picture is not only English — Dutch has dagdroom, German Tagtraum, Swedish dagdröm and Icelandic dagdraumur, each built from the same two blocks.
From day + dream. Compare West Frisian deidream (“daydream”), Dutch dagdroom (“daydream”), German Tagtraum (“daydream”), Swedish dagdröm (“daydream”), Icelandic dagdraumur (“daydream”).
Etymology from Wiktionary, CC BY-SA