Weaning was the process of gradually reducing one's dependency on a substance or device.
In 2151, Trip Tucker saw a Lorillian mother weaning her son off of methyl oxide and onto oxygen, and attempted to stop her, believing she was suffocating her child. T'Pol explained what she was doing, which surprised Tucker. (ENT: "Broken Bow")
In 2367, upon Junior's departure from the USS Enterprise-D, Captain Jean-Luc Picard congratulated Geordi La Forge and Leah Brahms for having "weaned the baby", as they had made the "milk" (energy) it was draining from the starship unpalatable to the lifeform . (TNG: "Galaxy's Child")
In 2368, despite being aware that Clara Sutter ought to be weaned off her imaginary friendship with Isabella, Deanna Troi had some misgivings about stealing her childhood from her. (TNG: "Imaginary Friend")