Nematode(noun) – any of a phylum (Nematoda or Nemata) of elongated cylindrical worms parasitic in animals or plants or free-living in soil or water
— called also roundworm
This was word was encountered in “A Literary Visitor Strolls in From the Airport” by Charles McGrath
The sentence in which this word was used says ” Actually, instead of looking at individual buildings, it makes more metaphorical sense to think of New York as one enormous chunk of masonry that has been cut up and carved away. It says , This is the ultimate polis, through which humans move like nematodes.”
The author uses a metaphor describing how humans move like nematodes. When a Nematode moves, it looks as though it’s body is rapidly squirming around or as though it’s whipping its body side to side to move. I think that the author is trying to describe the movement of commuting New Yorkers.