# X not defined error, even though it is?

**URL:** <https://discourse.julialang.org/t/x-not-defined-error-even-though-it-is/20714>\
**Category:** General Usage\
**Created:** [February 12, 2019, 5:34pm UTC](https://discourse.julialang.org/t/x-not-defined-error-even-though-it-is/20714 "2019-02-12T17:34:06Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![ExpandingMan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/expandingman/32/866_2.png) [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Post date:** [February 12, 2019, 5:37pm UTC](https://discourse.julialang.org/t/x-not-defined-error-even-though-it-is/20714/2 "2019-02-12T17:37:17Z")

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I believe that the [notorious global scope issue](https://discourse.julialang.org/t/another-possible-solution-to-the-global-scope-debacle/15894) is at play here, but, more importantly, `const` means constant, so if you declare something `const`, you should not attempt to assign it.

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_[View the full topic](https://discourse.julialang.org/t/x-not-defined-error-even-though-it-is/20714)._