I heard it through the grapevine

Are you singing the song? That’s good, but this phrase did not come from the popular song. Today, the phrase means to acquire information from an informal source. The term originates from the 1840s with the creation of the telegraph.

The telegraph introduced a means of rapid communication. The proliferation of poles and wires for the telegraph spread across regions like a giant grapevine. This led to the term ‘grapevine telegraph.’ This new term distinguished between the new telegraph system and the old word-of-mouth means of communication. People would utter 'I heard it on the grapevine' to indicate that they received genuine news, instead of unsubstantiated gossip.

In Australia, the term ‘bush telegraph’ persisted referring to networks of communication that passed on information about police movements to convicts.

That’s where the title of the popular song came from. Now you can listen to the Marvin Gaye version of the song.