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Just a small notation question from this Wikipedia page:

The absolute Galois group of a finite field $K$ is isomorphic to the group $\hat{\mathbb{Z}}=\lim_{\leftarrow} \mathbb{Z}/n\mathbb{Z}.$

What does the $\displaystyle\lim_{\leftarrow}$ part mean? Why is it written like that?

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    lim←Z/nZ. can be shown isomorphic to direct product of all Zp p-adics2012-12-31

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It is used to denote the inverse limit as opposed to the notation $\displaystyle\lim_{\to}$ which is used to denote the direct limit.