[1] XQuery and XPath Full Text 3.0 (2015-11-20 06:32:18 +09:00 版) http://www.w3.org/TR/2015/REC-xpath-full-text-30-20151124/#TokenDef

A token is a non-empty sequence of characters returned by a tokenizer as a basic unit to be searched. Beyond that, tokens are implementation-defined.