This is the 897th most frequent Chinese word.
梦想
"梦想" means "dream" or "aspiration."
梦想 here is used as a noun to mean 'dream' or 'aspiration'.
我的梦想是成为一名医生。
My dream is to become a doctor.
In this sentence, 梦想 is used as a verb, meaning 'to dream about' or 'to aspire to'.
年幼时，她梦想过飞到太空探索未知的星球。
As a child, she dreamed of flying into space to explore unknown planets.
梦想 is again a noun referring to one's aspirations, employed in an inspirational context.