# Why is the zipper on a part of pants called a fly ? **URL:** \ **Category:** Factual Questions\ **Created:** [December 4, 2002, 9:32pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525 "2002-12-04T21:32:30Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![dragongirl](https://avatars.discourse-cdn.com/v4/letter/d/b38774/32.png) [@dragongirl](https://boards.straightdope.com/u/dragongirl)\ **Post date:** [December 4, 2002, 9:32pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/1 "2002-12-04T21:32:30Z")
Why are zippers on pants called flies ? That pretty much says it all. Thanks. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [December 4, 2002, 9:49pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/2 "2002-12-04T21:49:39Z")
It’s not. The zipper is called a zipper. The fly is the opening in the front of the pants, whether with a zipper, buttons, velcro, or open to the elements. Properly speaking, the fly is the flap of cloth covering the opening, and is etymologically related to other protective flaps of cloth, such as a tent fly. ---
**Author:** ![Ezstrete](https://avatars.discourse-cdn.com/v4/letter/e/7ea924/32.png) [@Ezstrete](https://boards.straightdope.com/u/Ezstrete)\ **Post date:** [December 4, 2002, 10:49pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/3 "2002-12-04T22:49:47Z")
A fly was a fly long before the zipper came into usage-----and ,if you go back far enough in time ,it was just a long flap that was tucked into the opening for decency and comfort. Sorta like a tent flap. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [December 4, 2002, 11:11pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/4 "2002-12-04T23:11:03Z")
OK, so why is _the opening_ called a fly? ---
**Author:** ![Ezstrete](https://avatars.discourse-cdn.com/v4/letter/e/7ea924/32.png) [@Ezstrete](https://boards.straightdope.com/u/Ezstrete)\ **Post date:** [December 4, 2002, 11:40pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/5 "2002-12-04T23:40:26Z")
Originally it probably wasn’t called a fly. but it might have become so through common usage-----since it was the place where the fly was located. Open your fly—close your fly----your fly is open —your fly is closed. Or they coulda just said,“Hey-----the hole in y’pants is open-close yer fly,guy!” ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [December 5, 2002, 12:43am UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/6 "2002-12-05T00:43:57Z")
I’ll contribute a few facts from the OED. I don’t promise you that my surmises are correct, but so be it. The word fly(flies) appears in _theater_ usage in England in 1805. > [@](#): > > The space over the proscenium, including the upper mechanism and the galleries on each side from which it is worked In that same time frame(1810) we see that the roof of a tent was referred to with the same spelling(flies): > [@](#): > > The main part of the operation of pitching the tent, consisting of raising the flies. The fly on a pair of pants appears in 1844 > [@](#): > > Open in front, with a Fly and Five Buttons. in a military list of regulations. Not hard to imagine that military type who lived in and pitched tents might coin the term “fly” to apply to the flap that covered the opening in their trousers. ---
**Author:** ![Ficer67](https://avatars.discourse-cdn.com/v4/letter/f/c57346/32.png) [@Ficer67](https://boards.straightdope.com/u/Ficer67)\ **Post date:** [December 6, 2002, 1:47pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/7 "2002-12-06T13:47:16Z")
Every once in a while, something flies out of those things ---
**Author:** ![malaka](https://avatars.discourse-cdn.com/v4/letter/m/ecc23a/32.png) [@malaka](https://boards.straightdope.com/u/malaka)\ **Post date:** [December 6, 2002, 2:02pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/8 "2002-12-06T14:02:09Z")
XYZPDQ ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [December 6, 2002, 3:24pm UTC](https://boards.straightdope.com/t/why-is-the-zipper-on-a-part-of-pants-called-a-fly/140525/9 "2002-12-06T15:24:50Z")
Just a conjecture. Couldn’t it have anything to do with flying a flag?