The top of a hundred-foot pole; a Buddhist metaphor for reaching the highest possible level of enlightenment or achievement. Often used with 百尺竿头，更进一步 bǎi​chǐ​gān​tóu​gèng​jìn​yī​bù to encourage someone to continue striving for progress even after achieving great success.

more; even more; still more (used to indicate a higher degree)

to advance by one step physically or metaphorically