# Differences between a library and a module in julia?

**URL:** <https://discourse.julialang.org/t/differences-between-a-library-and-a-module-in-julia/22879>\
**Category:** General Usage\
**Created:** [April 7, 2019, 3:22pm UTC](https://discourse.julialang.org/t/differences-between-a-library-and-a-module-in-julia/22879 "2019-04-07T15:22:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![bsnyh](https://avatars.discourse-cdn.com/v4/letter/b/ce7236/32.png) [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Post date:** [April 7, 2019, 3:22pm UTC](https://discourse.julialang.org/t/differences-between-a-library-and-a-module-in-julia/22879/1 "2019-04-07T15:22:41Z")

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I’m mainly interested in the `Base` library in Julia. It looks like I can add my defined method as the following.

```julia
julia> import Base

julia> function Base.rand()
            println("my base")
       end

```

I tried

```julia
help?> Base
search: Base basename AbstractSet Broadcast broadcast broadcast! AbstractString AbstractDisplay set_zero_subnormals get_zero_subnormals

  The base library of Julia.

```

So, Base is a library in Julia. For my understanding, a library is a bunch of modules together? Is this true?

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**Author:** ![chakravala](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chakravala/32/6832_2.png) [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Post date:** [April 7, 2019, 3:38pm UTC](https://discourse.julialang.org/t/differences-between-a-library-and-a-module-in-julia/22879/2 "2019-04-07T15:38:41Z")

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I don’t believe that the word library as used here is a technical term. `Base` is a module.