Definition is what the last run wrote. On a term a person has
worded themselves the read path serves UserDefinition here instead,
so a caller always gets the wording the catalog stands behind.
deleted_atstring
descriptionstring
idstring
metadataobject
namestring
parent_term_idstring
tagsstring[]
updated_atstring
user_definitionstring
UserDefinition is the wording a person gave the term. Ingestion
reads it and never writes it, so it survives every run.