Variant: one of the member schemas of the meta-schema union. Nine are closed maps: schema/struct-schema, schema/map-schema, schema/list-schema, schema/scalar-schema, schema/link-schema, schema/include-schema, schema/anyof, schema/var-schema and schema/literal-schema. The other four are the bare string, integer, boolean and null kinds, which are literals.

See also

Discriminated union: how a value picks its variant.

Union schema: the anyOf construct the meta-schema uses.

Primitive: an instance of the meta-schema, which is a different thing.

Closed map: why each variant rejects stray keys.