字面意思是伸手摘星星，實際意思是

to want or try to get something that is difficult or impossible to get

追求難以實現(xiàn)的東西;要做比登天還難的事情;心比天高，延伸出“追尋遠大目標”的意思。

比如說

His parents always taught him to dream big and reach for the stars.

他的父母總是教導他要勇敢作夢、立志高遠。

"Reaching for the stars" is a good term to use when you want to motivate someone to dosomething difficult.

當你想激勵某人去做困難的事情時，reaching for the stars是一個很好的表達。