**Attribute
**A parameter to an XML element (specified in the begin tag) that is
composed of an attribute name and a value.

**Block level tag
**A term used for categorizing display style (math in between paragraphs)
MathML elements.

**Cascading Style Sheets (CSS) **A
mechanism that allows authors and readers to attach style (e.g.
fonts, colors and spacing) to HTML documents.

**Character Data (CDATA)
**A SGML data type for raw text which does not include markup or
entity references.

**Character level tag
**A term used for categorizing inline (math as part of a paragraph)
MathML elements.

**Content element
**MathML elements which explicitly specify the meaning of a portion of a
MathML expression.

**Document Type Definition (DTD) **In SGML or XML a formal
definition of the tags and the relationship among the
data elements (the structure) for a particular type of document.

**Entity reference
**A sequence of ASCII characters of the form
&

**Extensible Markup Language (XML)
**A simple dialect of SGML intended to enable generic SGML to be served,
received, and processed on the Web.

**Fence tags
**A matched pair of bracketing tokens like parentheses, braces, and
brackets.

**Mathematical Markup Language (MathML)
**The markup language (specified in this document) for describing
mathematical expression structure,
together with a mathematical context.

**MathML element
**An XML element which describes part of the logical structure of a MathML
document

**Multi-purpose Internet Mail Extensions (MIME)
**A set of specifications that offers a way to interchange text in
languages
with different character sets, and multi-media content among many different
computer systems that use Internet mail standards.

**OpenMath
**A general representation language for communicating mathematical
objects between application programs.

**Parsed Character Data (PCDATA)
**A SGML data type for raw text occurring in a context in which
markup and entity references may occur.

**Presentation elements
**MathML tags and entities intended to express the syntactic structure
of math notation.

**Presentation layout schema
**A presentation element that can have other MathML elements as content.

**Presentation tokens
**A presentation element that can have only parsed character data
as content.

**Standard Generalized Markup Language (SGML)
**An ISO standard (ISO 8879:1986) which supplies a formal notation for
the definition of generalized markup languages via DTDs.