Sentence:  The <WSD>motifs</WSD> of impersonal interdependence and insulation of residential communities have polarized ; the schism between central city and suburb , Negro and White , blue collar and white collar can be viewed as symptomatic of this deeper polarization of trends in the metropolis . 
Meaning of the word marked with <WSD> tags:  a unifying idea that is a recurrent element in literary or artistic work