When you use the phrase ‘Pull The Plug’ you are referring to the act of putting a stop to someone’s plans or activities. This term is also used in a literal fashion to describe the intentional act of turning off a hospital life-support system.
Example of use: “Jeff wants to keep paying for cable, but Mary’s sick of paying the bill every month.
She’s planning to pull the plug on the cable company and watch TV online instead.”
No one knows for certain when the term ‘pull the plug’ originated, however its current meaning came into being after the invention of electricity. Household appliances with plugs weren’t common until the early 1900s, with the first practical vacuum cleaner arriving around 1907 and the first toaster in 1909.