Lid/lɪd/ Definition 1 of 4Pro Tip 1/3Container Closure Used to describe the top part that closes containers like jars, boxes, or pots. Don’t forget to replace the lid on the cookie jar. Pro Tip 2/3Secrecy Metaphor 'Lid' is often used metaphorically to suggest preventing secrets from being known. The report put a lid on the scandal. Pro Tip 3/3Seal Tightly Lid implies a tight fit to protect contents, prevent spills or keep things fresh. Make sure the lid is tight, or the milk might spoil.