A standard and a specification are two different concepts, although these terms are sometimes used interchangeably.
A standard is documentation established by consensus of subject matter experts and approved by a standards authority that provides rules, guidelines or characteristics for activities or their results (ISO/IEC Guide 2:2004).
A specification is documentation of a precise requirement or list of requirements, which has not necessarily received certification by an official standards authority.
Specifications may refer to standards. For example, National Geospatial Program product specifications may refer to industry standards, such as the Federal Geospatial Data Committee's Content Standard for Geospatial Metadata or the International Organization for Standardization's 191** suite of geospatial metadata standards.