The garden under the moonlight was covered in a dream-like mist, as if we were in a fairy tale.

dream-like 是由名词 dream（梦）加上后缀 -like（像...的）组成的形容词，字面意思是"像梦一样的"，引申为"梦幻般的"。 like 作为后缀时表示"像...的"，常与名词结合构成形容词，描述事物具有某种特征或性质。