backlog

/ˈbæk.lɒɡ/

noun

  1. A large log to burn at the back of a fire.

  2. A reserve source or supply.

  3. An accumulation or buildup, especially of unfilled orders, unconsumed products or unfinished work.

    "He went to work on Saturday to try to work through the backlog of papers on his desk."

  4. A log containing text previously read, as in text-based video games or chat rooms.

Etymology

From back + log. 1680s; originally a large log at the back of a fire. Figurative sense from 1880s, meaning "something stored up for later use". Possibly influenced by logbook as well.