The phrase "land of Nod" is used to describe a state of sleepiness or unconsciousness. There are several synonyms that can be used in place of this phrase, such as slumber, drowsiness, doze, snooze, and nap. These words all refer to a state of being where one is either asleep or on the edge of falling asleep. Other synonyms for "land of Nod" include dreamland, reverie, and trance, which suggest a deeper level of sleep or an altered state of consciousness. These words can be used interchangeably depending on the context and tone of the sentence.