openCurlyBracket
openingSalute
openParenthesis
openPunctuation
openSource
OpenURL
operatingSystem
operation
operationName
operator
opposition
OptativeMood
optional
optionalElement
optionalReflexive
optionalSyntacticArgument
oralEducationApproach
oralWithInterpreter
orchestrator
ord
order
ordinalAdjective
OrdinalNumeral
ordinalNumeral
ORG
Organisation
organisation
organization
organizationName
orgName
orientation
origDate
origin
original
OriginalChorus
originalEncoding
OriginalIncipit
originalMetadataLink
originalMetadataSchema
originalPageNumber
originalSource
OriginalTitle
OriginalTune
originatingApplication
originatingDatabase
originatingDatabaseName
originatingEntity
originatingInstitution
originatingPerson
origination
ISO 12620