noun

1. A large number of birds, especially those gathered together for the purpose of migration.

2. A large number of animals, especially sheep or goats kept together.

3. Those served by a particular pastor or shepherd.

Synonyms: bunch, gaggle, horde, host, legion, litter, nest, rabble

verb

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

   “People flocked to the cinema to see the new film.”

2. To flock to; to crowd.

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