A “lid” is what White House press secretaries use to indicate that there will be no news coming out of the White House that day. It can also be called a “Full Lid.”
A lid is typically called when the White House does not want to release any information about a key topic. They call a lid to give notice to journalists that no questions will be answered.
Although the term has been around for decades, it was popularized by fictional Press Secretary C.J. Cregg on TV show The West Wing.
Kelly O’Donnell: “The White House has again called a ‘lid’ meaning no other news is expected tonight.”