Nightmare: A frightening dream that usually wakes up the sleeper.
梦魇：通常会把睡眠者惊醒的可怕的梦。
Nonconscious: Not typically available to consciousness or memory.
非意识：记忆或意识中不存在的。
Non-REM (NREM) Sleep: The period during which a sleeper does not show rapid eye movement; characterized by less dream activity than during REM sleep.
非眼动睡眠：睡眠者没有快速眼球运动的时期；以梦活动少于快速眼动睡眠为特征。
Norm: Standard based on measurement of a large group of people; used for comparing the scores of an individual with those of others within a well-defined group.
规范：对一大群人进行测量的标准；用于比较一个人的分数与一个明确定义的组内其他人的分数。