Blockquote element

In HTML and XHTML, the blockquote element defines "a section [within a document] that is quoted from another source". The syntax is.

The  element is used to indicate the quotation of a large section of text from another source. Using the default HTML styling of most web browsers, it will indent the right and left margins both on the display and in printed form, but this may be overridden by Cascading Style Sheets (CSS)

The non-semantic use of the  element purely to indent text is deprecated by the W3C (World Wide Web Consortium) in the current (1999) HTML 4.01 Specification, which is also the basis for XHTML 1.0. The preferred approach is the use of CSS.

Usage
Related (X)HTML elements include the  and   elements for shorter, probably in-line, quotations and for citations respectively. An (X)HTML attribute specific to the  and   elements is   where the provenance of the material quoted may be given. If the quotation is in a language other than that of the main document,  and maybe   attributes may be relevant to specify the language of the quoted text and perhaps its direction, left-to-right or right-to-left. may be used for semantic or styling purposes.

Relationship to some wiki markup and usage
In many Wiki markup languages, the semantics and effect of HTML  is different from the use of an initial colon in a paragraph, which may be translated into an HTML   element enclosed within a   element. (That is a ‘data definition’ within a ‘definition list’, without there being any preceding ‘data term’ or  element).