The term that describes the optical trick of swelling columns at midpoint, which was used in the design of the Parthenon is entasis.
If you take a look at the ancient Greek columns, you will see that they are a bit wider in the middle - so the column is not completely straight, but rather swells up in the middle so as to "correct the visual illusion of concavity." It was often used by artists in the ancient Greek times.
Answer: jongleurs
Explanation: Jongleurs were popular entertainers in medieval France. They would travel around, performing in marketplaces, abbeys, castles for people and nobles. The acts included juggling, acrobatics, music, and reciting. The work they sang and recited was popular or traditional. In cases when they would be a permanent employee, they would become Trouvère or ménestrel, depending on what they would primarily do.
This profession later declined and started to die out as professional entertainers started to divide their roles between acrobats, singers, musicians, actors, etc.
