date

primitive type

Base StructureDefinition for date Type: A date or partial date (e.g. just year or year + month). There is no time zone. The format is a union of the schema types gYear, gYearMonth and date. Dates SHALL be valid dates.

Official spec

Path	Card.	Type	Description & Constraints
date	0..*	—	Primitive Type date
.id	0..1	String	xml:id (or equivalent in JSON)
.extension	0..*	Extension	Additional content defined by implementations
.value	0..1	Date	Primitive value for date