Sentence:  The motifs of impersonal interdependence and insulation of residential communities have polarized ; the schism between central city and suburb , Negro and White , blue collar and <WSD>white</WSD> collar can be viewed as symptomatic of this deeper polarization of trends in the metropolis . 
Meaning of the word marked with <WSD> tags:  of or designating salaried professional or clerical work or workers