窗外那片未知的海洋门外那片未知的森林
[chuāng wài nèi piàn wèi zhī de hăi yáng mén wài nèi piàn wèi zhī de sēn lín]
The nickname means 'That unknown ocean beyond the window and that unknown forest outside the door'. Metaphorically speaking, it refers to the exploration and excitement of undiscovered or uncertain aspects in life and the future ahead.