"Ivan Petrovich Pavlov" is a proper noun, which refers to a specific person, not a common English word. He was a Russian physiologist, a scientist who studied how the body works, especially the digestive system. Pavlov is best known for his work with dogs, where he discovered something called "conditioned reflexes." This means he learned how animals could be trained to respond to certain signals or cues.
"When Pavlov rang a bell before feeding his dogs, they eventually started to salivate just at the sound of the bell, even when no food was present."