When Socrates went around questioning his fellow Athenians, seeking definitions for various abstract terms like virtue, justice, and love, he had great difficulty in finding clear meanings. But he had much better success with simpler and more concrete words. In his day there seemed little difficulty in defining a shoemaker, a physician, a sailmaker, or a musician.
A naive but popular view holds that each word should have a definite meaning, so that if you once grasp the meaning, you have a firm grip on reality. Two or three centuries ago, for example, this was generally true for medicine. There was anatomy, and everyone knew what anatomy was. There was materia medica, and everyone knew what that was. If a professor held a chair in the practice of physick, his activities were quite clearly understood by everyone.
What’s in a Name?. JAMA. 2015;314(9):954. doi:10.1001/jama.2014.11958