Sentence:  there is a concealed <WSD>bias</WSD> within the spheroid 
Meaning of the word marked with <WSD> tags:  In the games of crown green bowls and lawn bowls: a weight added to one side of a bowl so that as it rolls, it will follow a curved rather than a straight path; the oblique line followed by such a bowl; the lopsided shape or structure of such a bowl. In lawn bowls, the curved course is caused only by the shape of the bowl. The use of weights is prohibited.(from 1560s)