Why Do Jazz Musicians Call a Spontaneous Session a “Jam” and How Did the Word Originate?

All musicians refer to an informal and exhilarating musical session as “jamming,” but the term first surfaced in the jazz world during the 1920s.

“Jam” in jazz is a short, free, improvised passage performed by the whole band.

It means pushing or “jamming” all the players and notes into a defined free-flowing session.

And just like the preserved fruit “jammed” into a jar, a musical jam is sweet!

Preserved fruit was first called jam during the 1730s simply because it was crushed, then “jammed” into a jar.

To be “in a jam” has the same origin and means to be pressed into a tight or confining predicament.

Jamming radio signals is a term from World War I and means to force so much extra sound through a defined enemy channel that the original intended message is incoherent.

All this is from jam, a little seventeenth-century word of unknown origin that meant to press tightly.