English Reference
noun · verb

backlog

n. · v.
US /ˈbæˌkɫɑɡ/ UK /bˈæklɒɡ/ back·log UK spelling backlog's, backlog's, backlogging

  1. 01 B2 Upper Intermediate

    n.a pile of work or tasks that you have not finished yet.

    n.an accumulation of tasks, orders, or data that has built up and is awaiting processing or completion.

    Simple

    I need to stay late tonight to clear the backlog of emails from my holiday.

    In context

    The department struggled to address the significant backlog of visa applications that had accumulated during the three-month administrative strike.

    Usage

    Often used with the verb 'clear' or 'tackle'.

  2. 02 C1 Advanced InformalTechnical Computing

    n.a list of messages or text that you can look back at in a game or chat room.

    n.a stored record of previously displayed text or dialogue, typically accessible via a scroll-back feature in software.

    Simple

    If you missed the instructions, you can check the game's backlog to read them again.

    In context

    The visual novel includes a backlog feature, allowing players to review previous dialogue choices before making a critical decision.

  3. 03 C2 Proficiency Technical

    v.to let work or items build up instead of finishing them.

    v.to accumulate or allow to build up as a reserve or unfinished pile.

    Simple

    Orders began to backlog as soon as the main shipping port closed.

    In context

    The system was designed to backlog incoming requests during peak hours to prevent a total server collapse.

    Usage

    Used both transitively and intransitively.

That reduced the size of the initial decision backlog but shifted the problem to a new appeals backlog in the courts.

The Guardian· 27 Aug 2026

There are large backlogs in cases, as well as difficulties in carrying out post-mortems.

BBC News· 24 Aug 2026

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.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated