flock vs swarm

flock

noun
  • A large number of people. 

  • A large number of animals associated together in a group; commonly used of sheep, but (dated) also used for goats, farmed animals, and a wide variety of animals. 

  • Very fine sifted woollen refuse, especially that from shearing the nap of cloths, formerly used as a coating for wallpaper to give it a velvety or clothlike appearance; also, the dust of vegetable fibre used for a similar purpose. 

  • A number of birds together in a group, such as those gathered together for the purpose of migration. 

  • Those served by a particular pastor or shepherd.herd/flock 

  • Coarse tufts of wool or cotton used in bedding. 

  • A religious congregation. 

  • A lock of wool or hair. 

verb
  • To cover a Christmas tree with artificial snow. 

  • To coat a surface with dense fibers or particles; especially, to create a dense arrangement of fibers with a desired nap. 

  • To treat a pool with chemicals to remove suspended particles. 

  • To congregate in or head towards a place in large numbers. 

swarm

noun
  • A mass of people, animals or things in motion or turmoil. 

  • A large number of insects, especially when in motion or (for bees) migrating to a new colony. 

  • A group of nodes sharing the same torrent in a BitTorrent network. 

verb
  • To fill a place as a swarm. 

  • To climb by gripping with arms and legs alternately. 

  • To overwhelm as by an opposing army. 

  • To breed multitudes. 

  • To move as a swarm. 

  • To teem, or be overrun with insects, people, etc. 

How often have the words flock and swarm occurred in a corpus of books? (source: Google Ngram Viewer )