1. n. [Well Completions]

Another term for lock, a downhole device, run and retrieved on slickline, that is placed and anchored within the tubing string to provide a setting point for flow-control equipment such as valves, chokes and plugs. The three main types of lock use different means of locating and securing: a slip lock locates and anchors anywhere within the correct size of tubing; the collar lock locates in the space within tubing collars; and the nipple lock locates within completion nipple profiles.

See: nipple