an accumulation of jobs not done or materials not processed that are yet to be dealt with (especially unfilled customer orders for products or services)
"The software update team is working overtime just to clear the massive backlog of bug reports from last quarter."
the large log at the back of a hearth fire
"The old fireplace still held a massive backlog of unburnt wood that refused to catch fire no matter how much I poked it."
A large log to burn at the back of a fire.
"The old fireplace was lined with a massive backlog of seasoned oak logs waiting to be fed into the flames."
accumulate and create a backlog
"The winter snowstorms have caused our road crew to accumulate and create a massive backlog of unplowed streets that will take weeks to clear."
To acquire something as a backlog, or to become a backlog
"The hospital's emergency room quickly became a backlog of patients after the storm hit."