Asset: In PBCore, any piece of content — such as a program, clip, or episode — can be defined as an asset.  One asset may exist in many different forms (for example, on DVD, on a U-matic tape in English, and on a VHS tape in French). If the content is the same, those would all be considered instantiations of the same asset.

Attribute: In XML, an attribute is a structure used to describe or provide more information about the data contained in an element.   Attributes are stored within the value of an element, like this: <pbcoreTitle titleType=“main”>Lassie</pbcoreTitle>

Here, the element is pbcoreTitle, and the attribute titleType provides more information about the title.  

Class: A high-level group of related elements in XML

Container: A container element in XML is a way to group other elements together.  Container elements usually do not hold data themselves, but act as a bucket for sub-elements that do hold data.  

Element: An XML element is a way to store data in a self-explanatory manner, according to a structured and specific vocabulary.  For example, putting the information “Lassie” within a “pbcoreTitle” element tells anyone (or any machine) looking at the data that “Lassie” is the title of the asset. Attributes may be associated with any element: these provide even further detail about the data.

Instantiation: An instantiation is a manifestation of an asset that is embodied in physical or digital form, such as a tape, DVD, or digital file.  One asset can have many instantiations, but generally each instantiation holds the same intellectual content.

Metadata: Metadata is a set of data that describes and gives information about other data.  Metadata can include a wide variety of information, and different communities have different uses for metadata. Description (title, subject), technical information, or rights information are all types of metadata. Often there are different types of metadata needed for different purposes: structural metadata, technical metadata, preservation metadata. PBCore describes descriptive, structural and technical metadata (and can be considered by some uses to be preservation metadata as well).

Schema: An XML schema lays out rules for structuring an XML document in a specific way.  The PBCore schema specifies how PBCore information should be written in XML so that people and machines can consistently understand the information contained in PBCore documents by referencing the schema.   

XML: Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format which is both human-readable and machine-readable. It is defined by the W3C‘s XML 1.0 Specification and by several other related specifications.

XSD: An XSD is the document that defines an XML schema.  It can be used to validate other XML documents to make sure that they are complying with the rules of the schema.