What does XSD stand for?

1 Namespace considerations     3. 2 Special Built-in Datatypes anySimpleType · anyAtomicType     3. 3 Primitive Datatypes string · boolean · decimal · float · double · duration · dateTime · time · date · gYearMonth · gYear · gMonthDay · gDay · gMonth · hexBinary · base64Binary · anyURI · QName · NOTATION     3. 4 Other Built-in Datatypes normalizedString · token · language · NMTOKEN · NMTOKENS · Name · NCName · ID · IDREF · IDREFS · ENTITY · ENTITIES · integer · nonPositiveInteger · negativeInteger · long · int · short · byte · nonNegativeInteger · unsignedLong · unsignedInt · unsignedShort · unsignedByte · positiveInteger · yearMonthDuration · dayTimeDuration · dateTimeStamp 4 Datatype components     4. 1 Simple Type Definition.

RELAX NG schemas may be written in either an XML based syntax or a more compact non-XML syntax; the two syntaxes are isomorphic and James Clark's conversion tool - 'Trang', can convert between them without loss of information. RELAX NG has a simpler definition and validation framework than XML Schema, making it easier to use and implement. It also has the ability to use datatype framework plug-ins; a RELAX NG schema author, for example, can require values in an XML document to conform to definitions in XML Schema Datatypes.