1a large natural elevation of the earth’s surface rising abruptly from the surrounding level; a large steep hill:we set off down the mountainthey sought refuge in the mountains [as modifier]:a mountain peak
2 (a mountain/mountains of) a large pile or quantity of something:a mountain of paperwork
[usually with modifier] a large surplus stock of a commodity:a butter mountain
if the mountain won't come to Muhammad, Muhammad must go to the mountain
proverb if someone won’t do as you wish or a situation can’t be arranged to suit you, you must accept it and change your plans accordingly.
[with allusion to a well-known story about Muhammad told by Bacon (Essays xii)]