# Begin/end a logical block?

Can I create a logical block (like HTML div element), so I can apply features like \centering locally, but not affect the outside environment?

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You can use them in a group \bgroup.....\egroup. Whatever is used is applied only within that group. – Harish Kumar Sep 15 '12 at 2:30

Yes. The most basic of these blocks are braces { (for opening) and } (for closing). You can also use \begingroup and \endgroup or \bgroup and \egroup.
When defining your own environment <env>, using \begin{<env>} ... \end{<env>} necessarily forms a group, localizing most modifications.