Sentence:  The extension caused fury in Hampstead, where southbound trains began to arrive fully loaded with the <WSD>hoi polloi</WSD> of rapidly growing Edgware, Burnt Oak, Colindale, Hendon, Brent and Golders Green. 
Meaning of the word marked with <WSD> tags:  The common people; the masses. (Used with or without the definite article.)