lay-in /ˈleɪˌɪn/noun 3lay in verb 3forms 4 noun3 •A shot in which the ball is tossed directly into the basket from near the rim. •(informal) An instance of sleeping in. •Permission to sleep in late, typically for health reasons and granted by a doctor or nurse. lay in verb3 •To put (something) aside for future use.to lay in a stock / store / supply of something •To add (something) to a painting, especially directly onto the blank canvas in the early stages of the work.She uses a round brush to lay in the background. •To give a lay-in; to allow or require one to remain in one's cell, rather than work, due to injury or illness. formslaid in · laying in · lays in · lay-ins