What is the meaning of the word "dream"?

Definitions:

a fantastic but vain hope, from fantasies induced by the opium pipe noun
- I have this pipe dream about being emperor of the universe.
a series of mental images and emotions occurring during sleep noun
- I had a dream about you last night
a state of mind characterized by abstraction and release from reality noun
- They went about their work as if in a dream.
experience while sleeping verb
- They claim to never dream.
imaginative thoughts indulged in while awake noun
- The jester lives in a dream that has nothing to do with reality.
someone or something wonderful noun
- this dessert is a dream