This issue was originally reported by Steven Taschuk.

Part 2: Datatypes frequently defines the lexical representation of one
type as a "truncation" of that of another, without ever defining what
is meant by this term. Sometimes it seems to have the conventional
meaning of omitting characters from one end of a string, as in:

The lexical representation for gYear is the reduced (right truncated)
lexical representation for dateTime: CCYY. [section 3.2.11.1] Other
times the omitted characters are replaced by other characters, as in:

The lexical representation for gDay is the left truncated lexical
representation for date: ---DD . [section 3.2.13.1] It's not difficult
to understand what is meant, but the document overall aspires to (and
for the most part handily achieves) a higher standard of
precision. For consistency, I'd like to see the term defined in 1.1.

See mail from: Steven
Taschuk. (http://lists.w3.org/Archives/Public/www-xml-schema-comments/2002OctDec/0128.html
)

This is R-190.  On the 11/21/2008 telcon we agreed to add to the 1.1
Requirements and classify as "Clarification without Erratum"

This item was discussed in the meeting of 2004-05-12
(http://www.w3.org/XML/Group/2004/05/xml-schema-ftf-minutes.html).

...

The term 'truncation' is no longer used in discussing these lexical
spaces; it is hoped that this addresses the concern adequately.