"Lid opening" refers to the action of uncovering or revealing something that was previously hidden or closed. It implies discovering a secret, revealing the truth, or uncovering something unexpected. Full definition
The identity becomes clearer when the trunk lid opens, revealing the lithium - ion battery pack. (automobilemag.com)
Cover (leaving lid open a crack if necessary) and simmer on the lowest heat for about 2 1/2 — 3 hours, stirring occasionally, until the meat is very tender. (easynaturalfood.com)
Leave top lid open so grids begin to cool. (amazon.com)