Verb
(transitive, idiomatic, Britain) To stop doing a regular activity. Often a job or studies.
I've had enough of working nights, so I'm going to jack in my job.
I'm going to jack my job in.
(music recording, computing, electronics) To insert an electronic coupling into a receptacle; to connect to something, whether involving a physical medium or not.
(science fiction) To connect a brain directly to a computer.
Source: en.wiktionary.orgA cable from the jack in the wall is attached to the input of the box, and an output cable from the box is attached to the television, usually the RF-IN or composite input on older TVs. Source: Internet
The normal rule is that if the picker has the jack of diamonds, whether as a result of the deal or picking up the jack in the blind, the picker must play alone. Source: Internet