# Question about Foo or foo?

**URL:** <https://discourse.julialang.org/t/question-about-foo-or-foo/82091>\
**Category:** General Usage\
**Created:** [June 1, 2022, 10:56pm UTC](https://discourse.julialang.org/t/question-about-foo-or-foo/82091 "2022-06-01T22:56:30Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Raymond](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/raymond/32/36557_2.png) [@Raymond](https://discourse.julialang.org/u/Raymond)\
**Post date:** [June 1, 2022, 10:56pm UTC](https://discourse.julialang.org/t/question-about-foo-or-foo/82091/1 "2022-06-01T22:56:30Z")

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Dear all,

I am new to Julia. And I often see many people using Foo or foo in their codes.

So what does `Foo` or `foo` mean? Why so many people like to use it?

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**Author:** ![jar1](https://avatars.discourse-cdn.com/v4/letter/j/c0e974/32.png) [@jar1](https://discourse.julialang.org/u/jar1)\
**Post date:** [June 1, 2022, 10:57pm UTC](https://discourse.julialang.org/t/question-about-foo-or-foo/82091/2 "2022-06-01T22:57:06Z")

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> **[Foobar](https://en.wikipedia.org/wiki/Foobar)**
>
> The terms foobar (/ˈfuːbɑːr/), foo, bar, baz, and others are used as metasyntactic variables and placeholder names in computer programming or computer-related documentation. They have been used to name entities such as variables, functions, and commands whose exact identity is unimportant and serve only to demonstrate a concept.
> It is possible that foobar is a playful allusion to the World War II-era military slang FUBAR (Fucked Up Beyond All Repair).
> According to an Internet Engineering Task ...

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**Author:** ![kevbonham](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kevbonham/32/216165_2.png) [@kevbonham](https://discourse.julialang.org/u/kevbonham)\
**Post date:** [June 1, 2022, 11:07pm UTC](https://discourse.julialang.org/t/question-about-foo-or-foo/82091/3 "2022-06-01T23:07:11Z")

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It’s not just Julia, this is a common practice in programming languages as stand-ins in examples. In Julia, the convention is that variables and function names are lowercase, and types / modules are uppercase, so `foo = 42` or `bar() = "Hello, World!"`, or

```julia
struct Foo
    bar
end

```

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**Author:** ![Raymond](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/raymond/32/36557_2.png) [@Raymond](https://discourse.julialang.org/u/Raymond)\
**Post date:** [June 1, 2022, 11:10pm UTC](https://discourse.julialang.org/t/question-about-foo-or-foo/82091/4 "2022-06-01T23:10:33Z")

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@jar1 @kevbonham Thanks for your reply.