The word 'mast' means

The fair breeze blew, the white foam flew,    
The furrow followed free;    
We were the first that ever burst    
Into that silent sea.    
Down dropt the breeze, the sails dropt down,    
T was sad as sad could be;    
And we did speak only to break    
The silence of the sea!    
All in a hot and copper sky,    
The bloody Sun, at noon,    
Right up above the mast did stand,    
No bigger than the Moon.    
Day after day, day after day,    
We struck, nor breath nor motion;    
As idle as a painted ship    
Upon a painted ocean.    
— S.T. Coleridge