VOcabulary schema, version 1.0 (FVH 2007-09-01): A VOcabulary mainly consists of a simple list of entries which form the basis of the vocabulary. The only restrictions are that the VOcabulary have a name and a version number. Each entry in the vocabulary defines a token string which forms the actual basis of the vocabulary and can include additional information like short descriptions of what that token can mean within the context and what equivalences there are with the IVOA Standard Vocabulary (SV). The latter are needed in order to translate between vocabularies. The publishers of the vocabulary are encouraged to use the syntax rules used by the SV, e.g. a form for the token strings which is compatible with the UCD plus XML-namespace format. A reference to another VOcabulary used in the present one. This element is used to identify the namespace and its prefix, the latter used via "{prefix}:". The string content of the element is ignored. A string which can be optionally identified with a language via an ISO country code. A single definition, corresponding to one of possibly multiple uses of the vocabulary's token string, consisting of a short descriptive text, aliases, and/or a corresponding equivalent s in external vocabularies (e.g. SV+UCD1) used to perform translations. An optional short description of this particular definition (can be labeled as being in a particular language via the "lang" attribute). An optional free-format alias for the token string which are valid within the same context (may be more than one and can be labeled as being in a particular language via the "lang" attribute). An optional taxonometric/ontological equivalent of the label, expressed as semi-colon-separated concatenations of external tokens (may be more than one). The namespaces should be identified using prefixes, e.g. "ucd:" or "sv:". Definition of a single vocabulary entry. The token string which is the actual basis of the vocabulary (not to be confused with XML NMTOKENs). Top-level element of a named and versioned IVOA vocabulary, consisting of a description and a sequence of entries. A short description of the vocabulary (optional). The unique identifier of the VOcabulary, e.g. an IVOA-registered IVORN with the prefix "ivo://". The formal name of the vocabulary (required). The version number of the vocabulary (required).