I am reading 'The old man and the sea.' I've read this sentence as follows. 'But the bird was almost out of sight now and nothing showed on the surface of the water but some patches of yellow, sun-bleached Sargasso weed and the purple, formalized, iridescent, gelatinous bladder of a Portuguese man-of-war floating dose beside the boat.'
In this, What's the meaning of 'dose'? In dictionary I have, It only is remarked as 'a measured amount of it which is intended to be taken at one time.' With this meaning, I can't make sense of above sentence. please help me.:)