Webster's Revised Unabridged Dictionary · 1913

Backlog

Backlog (bak"log`; 115) , noun

[Back, a. + log.]

1.
A large stick of wood, forming the back of a fire on the hearth. Contrasted to forestick. [United States]
There was first a backlog, from fifteen to four and twenty inches in diameter and five feet long, imbedded in the ashes. — S. G. Goodrich
2.
An accumulation (of tasks or of materials) that were not performed or processed at the normal time and require attention; as, unexpected demand led to a large backlog of unfilled orders; politically motivated delays led to a large backlog of unconfirmed judicial appointments.