Final answer:
A 'jam session' is an informal gathering where musicians collaborate and improvise music in a relaxed setting.
Step-by-step explanation:
The term "jam seshes" refers to informal music sessions where musicians gather to play and improvise music together without a specific structure or setlist. These sessions can involve a variety of instruments and styles, depending on the participants and their musical preferences.
A "jam session" is usually intended for the musicians to experiment, socialize, and enjoy playing music in a relaxed environment. It is not a formal performance, but rather an opportunity for creativity and collaboration among artists.