The origin of the term backlog meaning:

  • a reserve or accumulation, as of stock, work, or business: a backlog of business orders.

probably refers to either the shipping term:


  • the meaning "arrears of unfulfilled orders" (1932) might be from, or suggested by, log (n.2), that is:

  • "record of observations, readings, etc.," 1842, sailor's shortening of log-book "daily record of a ship's speed, progress, etc." (1670s). The book so called because a wooden float at the end of a line was cast out to measure a ship's speed. (Etymonline)

or to a large piece of wood in the fireplace:


  • This word is used to describe a build-up of work or, more particularly, of unfulfilled orders. But this is a meaning it has had only since 1932 – was that the year that customer care became the vogue or was it the year that inefficiency first made an appearance? But the word’s origins were much more prosaic – it was used, principally in America and Canada, in the late 17th century to describe the largest log on a fire which was always put to the back. By the 1880s it was used figuratively to depict something stored for later use, just as the back log was the last to burn. (windowthroughtime.wordpresse)

Ngram: backlog.

The two assumptions have in common a piece of wood, but its usage and context was totally different. Is there any evidence to support one theory vs the other, or are there other possible credible assumptions to make?

  • intredasting---
    – user180089
    Jul 29, 2016 at 8:06
  • 4
    Funny, I always assumed the log in backlog was the sailor's log-book, backlog meaning the written down things that still have to be dealt with.
    – oerkelens
    Jul 29, 2016 at 9:29
  • You know, it's possible that the term, as currently used, is not derived from the log in the fire. My assumption has always been the case of the log book, transferred from the nautical use to bookkeeping use, with "back" referring to older (but somehow still relevant) entries.
    – Hot Licks
    Jul 29, 2016 at 15:58
  • @HotLicks - I agree that the nautical assumption sounds more logical, but other sources are for the "fireplace" one, which, I must admit, is an interesting one.
    – user66974
    Jul 29, 2016 at 16:04
  • @Josh61 - But everyone knows that the origin is always nautical!
    – Hot Licks
    Jul 29, 2016 at 16:45

1 Answer 1


Let's start with your definition of log from Online Etymology Dictionary.

"record of observations, readings, etc.," 1842, sailor's shortening of log-book "daily record of a ship's speed, progress, etc." (1670s)

So the log tells what the ship has done. It says what actions the pilot has taken. It records what the navigator has observed.

This definition of backlog says:

An accumulation of something, especially uncompleted work or matters that need to be dealt with: the company took on extra staff to clear the backlog of work

It may be reasonable to assume that backlog is a back-formation from log. The log says what the ship has done; the backlog says what uncompleted work or matters need to be done.

One proponent of the Agile methodology describes backlog as follows:

A backlog is a list of features or technical tasks which the team maintains and which, at a given moment, are known to be necessary and sufficient to complete a project or a release...

The log says what the ship has done; the backlog says what the team needs to do.

  • 1
    Good job, so what about the piece of wood traditionally placed at the back of the fire...for later use? A legend?
    – user66974
    Jul 29, 2016 at 16:56
  • 1
    In looking up many of the definitions of backlog, the piece of wood in the back comes up a lot. I'm thinking there may be a sense where this is "a source of energy for later." I'm also thinking that the forestick (new word to me) burns quicker and easier, and the central part of the fire dries out the backlog to help it burn later. Of course, this could be a source of work and income for the company in the future, or a source of work for the Agile team in an upcoming sprint.
    – rajah9
    Jul 29, 2016 at 17:33

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